[[quoteright:283:http://static.tvtropes.org/pmwiki/pub/images/quantum.jpg]]

->''"Theorizing that one can time travel within his own lifetime, Dr. Sam Beckett stepped into the Quantum Leap accelerator... and vanished. He awoke to find himself trapped in the past, facing mirror images that were not his own, and driven by an unknown force to change history for the better. His only guide on this journey is Al, an observer from his own time who appears in the form of a {{Hologram}} that only Sam can see or hear. And so Dr. Beckett finds himself leaping from life to life, striving to [[SetRightWhatOnceWentWrong put right what once went wrong]], and hoping each time that his next leap... will be the leap home."''
-->-- OpeningNarration

'''''Quantum Leap''''' is a 1988-1993 Creator/{{NBC}} CultClassic series about a scientist, played by [[Series/StarTrekEnterprise Scott Bakula]], caught in a malfunctioning TimeTravel experiment that bounced him back and forth in the past; the only way for him to move on from any time period he landed in was to change the life or lives of someone there for the better.

The show's explanation for the time travel was basically a HandWave -- the accelerator started Sam's leaps, but afterwards they were controlled by the PowersThatBe. The show also established that leaping affected Sam's memory -- ''and his own past''. This allowed the writers to regularly {{Retcon}} his skills and personal history (referred to in show as "the Swiss Cheese Effect") -- at least once a season he would suddenly be revealed to have completely forgotten about his musical career/doctorate in the specialty needed for the leap etc. (In other words, he SuddenlyAlwaysKnewThat.)

Great premise because it allowed an entirely new supporting cast and premise every week. If you didn't like one episode, chances are the next would be completely different. Also a cheap premise, since it made extensive use of existing period wardrobes, locations and sets, all but eliminating the need to build or make ''anything'' for the show, save for the very rare view of Project Quantum Leap itself. Many of the episodes recognizably played off the premises of popular movies, but went in a different direction.

The show employed several unique tropes. For one, though Sam would leap into a [[BodySurf variety of different hosts]], and he [[LieToTheBeholder would appear to all other people (including Al, at first) as whoever his new host was]], he would appear to the audience as Scott Bakula. Of course, OncePerEpisode, he would look into a mirror early on to give the audience an idea of whom he was portraying. The actor mirroring what he was doing would usually not be any good at it, much like when David Duchovny and Michael [=McKean=] did the ''DuckSoup'' dance on that episode of ''Series/TheXFiles''.

Though it had a sci-fi premise, ''Quantum Leap'' never really considered itself a sci-fi show. The time travel element was just a device to tell a variety of different stories, and the majority of episodes contained no fantastic elements at all, save for Sam's leaping and Al and Ziggy's guidance. (One of the few shows to air on both the USA and SciFi channels at the same time.) This was helped along by a rule (broken only twice intentionally, and twice by accident) that Sam could only time travel "within his own lifetime," so he couldn't be sent to prehistoric times or the future. This also helped keep costs down.

In late summer 2010, DonaldPBellisario announced that he was working on a [[TheMovie feature-film adaptation]] of the series.

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!!''Quantum Leap'' provides examples of:

* TheAce: Sam has six different doctorates, is a classically trained pianist, sings tenor, skilled in a number of martial arts, and fluent in several languages. However, his Swiss cheese memory means [[NewPowersAsThePlotDemands he only seems to remember them when it's relevant to the plot]].
** Anything Sam isn't that good at, Al usually does have the relevant skill and is able to help. For example, he once leaped into the life of an Italian mobster, and when people spoke Italian to Sam, Al(who spoke Italian fluently), acted as an interpreter.
* AllThereInTheManual: Apparently Sam's entire body leaps and he only takes on the appearance of whoever he is for that episode through the use of {{hammerspace}} or some other technobabble. This explains why he is able to perform physical feats that he should not be able to as a young kid, old man, old lady, chimpanzee, etc. This has led to other implications, such as the ability to conceive a child.\\\
Conversely, whoever Sam leaps into takes his place at the Project and takes on Sam's appearance, though since they are confined to the waiting room during Sam's leap, this seldom comes into play in the series. The episode "Honeymoon Express" acknowledges it during the Senate hearing to defund the project, where the senator in charge says that for all they know Sam lied about inventing time travel and uses this as a way of playing them off by claiming "Oh that's not really Dr. Beckett, it's the person he's leapt into inside his body."
* AmbiguouslyGay: A major factor in one episode. Sam leaps into a military school student who is being harassed because he might be gay. It's never determined if he really was gay or not, but Sam says it doesn't make a difference either way.
* ArbitrarySkepticism: For a series where characters utilize time travel and believe God Himself is somehow involved in their doings, this trope crops up more often than not. Sam believes in God, but not the devil. In some cases, Sam does this to Al, such as when he refuses to believe in ghosts or vampires. In a reverse, Al doesn't believe Sam when he claims to have seen an alien ship.
* ArsonMurderAndJaywalking:
-->'''Al:''' It's much worse than death... in two days, she goes home... she spends the rest of her life alone... without love... in [[PlaceWorseThanDeath Cleveland]].
* AssholeVictim: In the second season premiere "Honeymoon Express" Sam kills the psychotically possessive and murderous ex-husband of his host's new wife. This is the first time Sam has ever killed another person.
* AsHerself: Sam leaps into the life of Dr. Ruth Westheimer. Meanwhile the real Dr. Ruth analyzes Al's relationship issues in the "waiting room".
* AdventureTowns: Sam has been to major cities, small towns, even flying a plane once (which he did not know how)!!
* BadassBookworm
* BlackLikeMe: Sam leaps into an elderly African-American man in Red Dog Alabama in 1955 and does not realize it until he sits down at the lunch counter and see his host's reflection. This happens again with an AA Medical student in the Watts riots in 1965, and with a U.S. Navy SEAL in Vietnam in 1970.
* BeenThereShapedHistory: Occasionally, Sam runs into YoungFutureFamousPeople and inspires them by showing them one of the things that they're famous for without realising it until after. The cast and crew referred to these events as "Kisses With History."
* BeepingComputers
* BelligerentSexualTension: "A Hunting We Will Go" is '''all about''' this trope. Sam leaps into a bounty hunter and has to deal with a female criminal who does everything she can to escape (including assaulting him, getting ''other people'' to assault him, and trying to ShowSomeLeg). They repeatedly comment on how much they hate one another, and yet still have a few passionate make-out scenes. For what it's worth, Al sees right through it because he had a similar relationship with one of his wives.
* BerserkButton: Sam ''hates'' all forms of racism or intolerance, it being one of the few things that makes him genuinely angry. Meanwhile, Al, despite his womanizing ways, reacts quite badly to the mistreatment of women.
** Sam's hatred of racism is such that when one leapee is a young man who joined the Ku Klux Klan because of peer pressure, Sam is so disgusted he initially flat-out refuses to do ''anything'' to help them and visibly struggles to keep up the charade--watch him literally choke on saying the "n-word" multiple times.
** Sexism becomes one for him after he spends time as a woman in TheSixties.
* BigBrotherWorship: Sam was said to view Tom this way. Apparently, Tom used this worship to help push Sam in the direction we all know he took.
* BigLittleMan: Sam leaps into a guy who works at a carnival. While he's checking out his new reflection in a funhouse mirror, one of the other carnies walks up and starts a conversation. At first we only see his reflection, which looks the same height as Sam, but when Sam turns to reply to him, he's revealed to be a dwarf.
* BittersweetEnding: "Mirror Image" and the series as a whole. [[spoiler:Sam ensures that Beth never remarries, which leads to her and Al being happily married and having four daughters. On the other hand, Sam never returns home]].
* BlackGalOnWhiteGuyDrama: In "So Help Me God," Sam leaped into a lawyer trying to prove a black woman innocent of the murder of the son of a rich white man in the 1950's. It turned out that [[spoiler:the woman, Delilah, had been in a abusive and at first not consensual relationship with him (possibly referencing how white men would often rape their female slaves/servants). When she was about to leave him and stop being a servant in his father's house, he attacked her and his own mother shot him to stop it.]]
* BlindingCameraFlash: This happens to Sam in "Blind Faith" when a reporter's flashbulb explodes in his face, temporarily blinding him. Since Sam is currently impersonating a blind person, this saves him from being exposed as a sighted impersonator.
* BodySurf
* BolivianArmyEnding: The finale.
* TheBoxingEpisode: "The Right Hand of God." Sam leaps into a boxer "owned" by a sisterhood of nuns. The episode reveals Al as something of a boxing aficionado, but it doesn't do Sam much good since holograms make poor boxing trainers. However, during the fight itself, Al shines: he waves his hands through Sam's opponent as targets for Sam to hit.
* BreakingBadNewsGently: The "you better sit down" line doesn't work that well when Sam is forced to be in dresses.
* BritishRockstar
** Sam leaps into one in "Glitter Rock."
** And while it has no real bearing on the plot, "Blind Faith" takes place during TheBritishInvasion as [[Music/TheBeatles a certain group]] arrives in town.
* ByTheEyesOfTheBlind: Children, animals, mentally disabled people can see Al, the psychic can see Sam and seems to sense Al's presence as well.
* CallingYourShots: Somewhat averted in the episode "Pool Hall Blues", where Sam leaps into a professional pool player. The game everyone plays is nine ball, and in nine ball the only ball you have to call before you sink is the 9.
* CassandraTruth
** In "Star Light, Star Bright," government agents inject Sam with a truth serum to question him about the UFO he saw. Instead, he goes on at length about ''himself'', including Project: Quantum Leap. He is generally thought crazy, but he raises some eyebrows when he mentions a secret level of government clearance that the leapee couldn't possibly know about.
** A few other times, Sam does purposefully try to tell people who he really is. It usually works, but as in "Killin' Time" and "Revenge of the Evil Leaper," it takes a heck of a lot of convincing. With the psychic who can see him, it takes no convincing whatsoever--she's pretty much figured it out right away.
* TheCastShowoff
** Sam leaps into a lot of musicians and dancers, the better to showcase Scott Bakula's impressive musical chops.
** Dean Stockwell also had opportunities now and then, such as when Al showed Sam how to dance at a Jewish wedding.
** And then there was the episode where Al rapped...
* CatchPhrase
** Sam would mutter "Oh boy..." upon arriving in a new "host" and assessing the situation.
** Al would often utilize the phrase, "Isn't this a kick in the butt?" once an episode at least in Season 1.
* ChainedToABed: Sam in "Moments to Live."
* ChasteHero: Sam, conveniently enough, because it would be a bad idea anyway. The man even turns down ''MarilynMonroe'', causing Al to call him "a stronger man than I". [[spoiler:Subverted in "Trilogy," where he falls in love with the woman he's supposed to be helping and accidentally gets her pregnant, causing their daughter to be a member of the Quantum Leap Project.]]
* ChekhovsGun: "Miss Deep South" contains a textbook example. Early in the episode, we see a conspicuously-placed poster advertising a Jerry Lee Lewis concert. Al even points it out to Sam. In the episode's final act, Sam is under pressure to maintain his leapee's original third-place finish in the pageant (since she used the money she won to go to school and become a doctor). Sam sees the poster again and decides to perform Lewis' signature song "Great Balls of Fire" for the talent competition. [[spoiler:The performance delights the crowd and the judges (and Al, who dances to the beat), and Sam is named the ''winner of the pageant''.]]
* ChivalrousPervert: Al been married five times, eyes up everything in a skirt, everything ''out'' of a skirt and even Sam when he's leapt into the body of a woman. But he genuinely likes women, doesn't do relationships just for sex, and he considers those who abuse women to be the lowest of scum.
* ChristmasEpisode
** Season 3's "A Little Miracle," where Sam and Al seek to change the Scrooge-like Blake for the better. As Sam says, [[YetAnotherChristmasCarol "We Scrooge him."]]
** Season 5's "Promised Land" takes place during Christmas, complete with decorations and the themes of family being a focus. Sam also gets to wish a Merry Christmas to his father, Jonathan.
* ChronicHeroSyndrome: Sam. Making the world a better place was his sole reason behind Project: Quantum Leap. In "Mirror Image," Al the Bartender claims that ''Sam himself'' may have been the one in control over his own leaps and could have quit the entire time, but subconsciously continued on because of his desire to help people meant that he never felt he had done enough. Throughout the episode, Sam stubbornly refuses to even entertain that idea, insisting that Al the Bartender is The-Man-Behind-The-Curtain in charge of Sam's leaps and the one not letting him come home.
** Al lampshades this trope in "Play Ball," telling Sam he always runs the risk of getting distracted from his goals because he wants to save everyone.
* ClearMyName: In Last Dance Before an Execution, Sam leaps into a death row inmate and must attempt to prove that he was actually railroaded by a district attorney more interested in a conviction record than actual justice. [[spoiler:In a subversion, Sam ends up confirming that the leapee ''is'' guilty; it is his also-condemned accomplice who was railroaded by the DA.]]
* {{Cliffhanger}}: Almost every episode ends with the start of Sam's next leap. Season 3 also ends with [[spoiler:Sam and Al inadvertently switching roles]] and Season 4 with [[spoiler:Sam leaping into Lee Harvey Oswald]].
* {{Confessional}}: In ''Leap of Faith'' (season 3, episode 3)
* ConspicuouslyLightPatch: Happened a few times with objects Al would walk through.
* ConspiracyTheorist: Sam's the only one willing to believe that Lee Harvey Oswald was the sole gunman. Al eventually accepts it...the day of the shooting.
* CoolOldGuy: Al. Despite being older he is a lot more knowledgable of modern pop culture than Sam is.
** When Sam leaps into a glam heavy metal singer, it's Al who coaches him on how to act like a rock star on stage.
-->'''Al:''' ''All you do is you go out there and you make an idiot out of yourself.''
* CrashCourseLanding: Happened once or twice (including the pilot), with Al having to talk Sam through it.
* CreatorCameo: The horror author who Sam leaps into in "The Boogeyman" is that episode's writer Chris Ruppenthal, while the parapsychologist who Sam leaps into in "A Portrait for Troian" is played by Donald P. Bellisario. Troian was played by series writer-producer Deborah Pratt, and named after their daughter [[PrettyLittleLiars Troian Bellisario]] -- who also appeared on the show (but not in this episode) and Bellisario's subsequent series ''Tequila and Bonetti'', ''Series/{{JAG}}'', ''First Monday'' and ''Series/{{NCIS}}'', as well as his only big-screen movie ''Last Rites''. Bizarrely, Donald P. Bellisario has a metafictional one in "Lee Harvey Oswald," where we see a portrayal of the younger version of Bellasario interacting with Oswald, as they ''did'' serve in the same military unit [[TruthInTelevision in real life.]]
** Additionally, in "Trilogy, Part 1," the man Sam leaps into for that episode is a sheriff played by James Whitmore, Jr, the director of that episode (among several in the series).
* CueCardPause
* CunningLinguist: Sam, apparently, though we rarely get to see him display this talent, save for one episode where he leaps into an archaeologist who can immediately read ancient Egyptian writing and another where he leaps into a man married to a Japanese woman and is able to converse fluently with her. At this point, Al reminds him that he speaks "7 modern languages and 5 dead ones".
* DeadAir: In the episode "Good Morning, Peoria", the air goes dead when an intimate conversation between the radio station owner and Sam (who has leapt into a DJ) extends past the end of the record. He picks it up well, though:
-->'''Sam:''' For the last couple of minutes you folks have been listening to something by Dull Needle and the Statics. A lot of people find it repetitive, [[TrueArtIsIncomprehensible I like to think of it as just plain old daring.]]
* DeadpanSnarker: Al
* DeathByChildbirth: The wrong righted in the pilot.
* DeadAllAlong: [[spoiler:One of the interpretations.]]
** [[spoiler:Stawpah in the finale. He leaps out after completing ''his'' mission and no one leaps back in. According to one of the locals, a Stawpah did exist, but died a couple decades earlier.]]
* DeusExMachina: Frequently used to get Sam out of the pickles he finds himself at the very start of a leap (i.e. the cliffhanger of the previous episode). He's strapped to the electric chair... but the phone rings and he's given a stay of execution. He's about to have to go on stage and perform, without even knowing what show it is... but it turns out he's an understudy and the billed actor shows up at the last second. Somewhat [[JustifiedTrope justified]] in that it's heavily implied that God Himself is controlling the leaps, so wouldn't put Sam in a completely impossible position unless it was about to change.
* DevilInDisguise: In one episode, Sam discovers that the "Al" who has been advising him is a fake, and is actually the Devil.
* DevilsAdvocate: [[PlayingWithATrope Discussed]] (and sometimes used) between Sam and Al.
* DieHardOnAnX: It's ''Heaven Can Wait'' with time travel.
* DidYouJustPunchOutCthulhu: During the HalloweenEpisode, Sam and {{Satan}} [[ItMakesSenseInContext try to strangle each other]]. [[BadassNormal Sam]] ''wins''.
* DirtyOldMan: Admiral Al Calavicci, contrasting the younger ChasteHero, Samuel Beckett. Al brags about his past love life, ogles all of the young women Sam encounters (often advising him to have sex with them, too), and makes very suggestive comments designed to [[ParentalBonus fly over the heads of younger viewers.]] When Sam finds out that dead bodies creep out Al, he quips, "Finally, something sexual you're ''not'' into." When the two switch places in one episode, ''Sam'' becomes the dirty pervert suggesting sex and getting distracted by attractive women.
* DisappearedDad: Al's own dad. After his mother split, Al's dad tried to provide for children, but work eventually took him overseas. Al was placed in an orphanage and Trudy in an institution until he could come back full-time. (He did apparently visit, though.) After some time, he came back for good and bought a house for them all to live in, but then he got sick and died.
* DisguisedInDrag: At the start of "M.I.A.," Sam leaps into an undercover cop dressed as a woman for a case. (He initially thought he had again leapt into a woman and was rather annoyed.)
** What should have tipped him (and the audience) was the fake boobs. Whenever Sam leapt into a woman, he just wore the clothes naturally. In this case, the detective was dressed up "to enhance enticement."
* DistaffCounterpart: The Evil Leaper obviously, but moreso her Observer Zoe, who's [[AllWomenAreLustful a horndog]] like Al (though much [[DeadpanSnarker snarkier]] and [[{{Jerkass}} ruder]]).
* DownLADrain: In the episode "Camikazi Kid" [sic] Sam leaps into a 17 year old racing enthusiast in San Gabriel Vally CA. He and the bad guy of the episode have their climactic race in the drains.
* EquivalentExchange: The people Sam replaces take his place in the now-recent-past-that-didn't-happen.
* EvilCounterpart: Not quite the Evil Leaper, since Sam talks her into a HeelFaceTurn, but her hologram partner Zoe is definitely one for Al, being a snarky horndog but completely lacking any redeeming traits like his compassion or sense of honor.
* ExpansionPackPast: The dramatic need for Sam or Al to have a personal stake in the plot each week meant that both leads pretty much define this trope. It's implied that Sam changes his own history after every leap, but retains all he's learned from each timeline; and it's explicitly shown to be the case in at least two instances.
* FailureIsTheOnlyOption
* {{Fanservice}}
** Sam frequently is shirtless, even in the opening credits. In one episode he [[SexySoakedShirt falls into a pond]] and spends the rest of the episode shirtless/in a towel.
** In "The Leap Back", when Sam is changing [[spoiler:before entering the Imaging Chamber so he can leap into the body Al's occupied (thus having them change places so Al's no longer the Leaper and Sam no longer the Observer)]] Ziggy comments "Great legs, doctor." Heterosexual female viewers and gay men everywhere nod in agreement.
** A naked Terry Farrell appears at the start of ''A Leap For Lisa''.
* FashionDissonance: A weird case: Al's choices in clothing were ''intentionally'' regrettable looking, when they weren't a navy uniform. WordOfGod states that this was done to differentiate the holographic Al from the people who were actually physically there. In-universe (particularly the novelizations), Al had a conscious preference for garish combinations. In a few episodes where Sam leaps to a time and/or place Al has a particular fondness for he will sometimes make an attempt to dress in period clothing only to put together colors and patterns that still manage to make him look appropriately terrible.
* FelonyMisdemeanor: In "Memphis Melody," Sam's actions accidentally cause Elvis not to get discovered. Al checks the changes to history and says that "Heartbreak Hotel" gets recorded by TheMonkees and "Blue Suede Shoes" by Tony Orlando and Dawn, to which he responds by miming throwing up.
* FogFeet: Sam leaps into a Vietnam vet who's lost both his legs. There's a mean orderly in the episode, and at one point when there's nobody else about Sam gets out of the wheelchair, walks over to the orderly, and slugs him. Since the orderly can only see Sam as the man he leaped into it looks to him like Sam is floating on air.
* ForWantOfANail: Usually played straight. Sam is contantly changing history in relatively small ways all things considered. While the people he encounters are certainly affected, the future itself isn't radically changed. This was true even when he interacted with real-life people, largely thanks to RubberBandHistory.
* {{Foreshadowing}}: In "Sea Bride," Al casually mentions his one true love. The very next episode is "M.I.A.", which greatly expands on this.
* ForegoneConclusion: You should already know at the start of "Lee Harvey Oswald" that Sam isn't going to save JFK. [[spoiler:He saves Jackie instead.]]
* {{Fratbro}}: Sam leaps into a Fratbro in an episod, and has trouble getting the GirlOfTheWeek to listen to him because she knows him to be a jockish ass. His fratty mates keep appearing and trying to embroil him in wacky high jinks, including raiding the office of "[[ActorAllusion Dean Stockwell]]".
* FreudianExcuse: "Dr. Ruth" hints that part of Al's relationship difficulties stems from his growing up in an orphanage.
* {{Gaslighting}}: In "A Portrait for Troian," Sam jumps into the body of a parapsychologist working with a young widow who insists the ghost of her late husband is haunting her. It turns out to be a plot by her brother to gaslight her.
* GlamourFailure: Sam's true form can be seen by little children, animals and psychics ("Temptation Eyes").
** Likewise, they also can see Al as a hologram.
** When Sam leaps into the body of a Vietnam veteran who lost both his legs, he causes an orderly to freak out when he stands up and appears to be ''floating'' in mid-air.
** When he comes into physical contact with another leaper, such as Alia and later Zoe, this causes them to see each's true form.
** One episode has Sam leap into an artist who believes himself to be a vampire. [[spoiler:At the end of of the episode, he looks into the mirror and realises he's ''[[RealAfterAll casting no reflection]]''.]]
* GiantSpaceFleaFromNowhere: The kidnappers from "Another Mother." While they get a fair bit of setup throughout the episode, we never find out what the deal is or why they're after their victim. It is strongly implied that they're child molesters and murderers, and that anyone will do.
* GivingRadioToTheRomans: Subverted in "The Leap Back." Ziggy's handlink accidentally travels back to 1945 with Al after the simo-leap, but it doesn't work because Ziggy doesn't exist yet. Indeed, when that episode's love interest is seen punching buttons on the dead handlink, Al comments that the device probably won't work again until 1999.
* GodTest: Sam has leaped into an illiterate murderer on the run who is holding a woman and her daughter hostage. He decides to drop TheMasquerade, telling her he's a doctor from the future in a TimeTravel experiment. She doesn't believe him. Then he notices her medical textbook, and she reveals that she's in medical school. So he has her quiz him on medical stuff to prove that he's telling the truth.
* GodWasMyCopilot: [[spoiler:Hinted at strongly.]]
* GoodGuyBar: The bar Sam finds himself in during the final episode.
* [[GranolaGirl Granola Guy]]: Al is shown to be ecologically-minded in several episodes, probably because so is Dean Stockwell.
* GuardianAngel: Angela from "It's a Wonderful Leap."
* HalloweenEpisode: "The Boogieman." Sam leaps into a horror novelist to stop a woman from being murdered. Problem is, other people die in the meantime and increasingly spooky incidents occur. [[spoiler:Turns out to be AllJustADream, though.]]
* HappilyAdopted: According to "Pool Hall Blues," a ten-year-old Al ran away from the orphanage and was reduced to picking pockets. The one person he tried it on was Charlie "Black Magic" Walters, who sympathized with Al and took him in. The intent was to find Al a family as they traveled, but it turned out to be Walters himself. A few months later, Walters was arrested for playing in a "Whites Only" bar and Al was sent back to the orphanage. Regardless, Al considers that the time the bright spot of his childhood and Walters as the first good person he ever met out in the real world.
* HauntedHouse: "A Portrait for Troian" is set at an estate where the former owners died horrible deaths and Troian (the current owner) believes her husband's ghost is trying to contact her. Sam thinks [[{{Gaslighting}} someone is just trying to drive Troian insane]], but Al thinks the house really is haunted. [[spoiler:Turns out they're both right. Troian's brother was trying to drive her crazy for her money, but housekeeper Priscilla is revealed to be a ghost.]]
* HeroicSacrifice: Of the non-dying variety, but still sacrifices.
** In "The Leap Home, Part 2: Vietnam," [[spoiler:Al helps Sam save his brother's life, giving up the chance to prevent his last three years of imprisonment in the process]].
** In "The Leap Back" and "Mirror Image," meanwhile, [[spoiler:Sam sacrifices chances at being home to help Al -- saving his life in the former and his marriage with Beth in the latter]].
* HeroicBSOD: Sam has one in "Black on White on Fire," set during the Watts Riots. The leapee's brother, Lonnie, takes the leapee's white girlfriend hostage in desperation. Sam manages to talk him down, ending the stand-off peacefully, but unfortunately Lonnie is then killed by police sniper-fire.
-->'''Al:''' ''(solemnly)'' Sam... you did it.\\
'''Sam''': ''(cradling Lonnie's body)'' Was it enough, Al? ''Was it enough?''\\
''(Sam leaps before Al can answer)''
* HeterosexualLifePartners: Sam and Al. As said in the last episode, there isn't anything they wouldn't do for each other. Discussed in "All Americans," where Chuey, the leapee's best friend, agrees to throw an important high school football game to clear his mother's debt with a slumlord, at the cost of his chance at being scouted for a sports scholarship which would be his only chance at going to college. He feigns injury to sit out, and Sam tries to figure out how to change things. Al tells him to just quit, too, because although Chuey is willing to sacrifice his own future he would never under any circumstances put his friend's chances at risk.
-->'''Sam:''' They're that close?\\
'''Al:''' Yeah. Just like you and me.
* HistoricalRapSheet: In one of the show's Kisses with History, Sam causes the Northeast Blackout of 1965 during an attempt to leap home.
* HollywoodAtheist: Al is revealed to be one in "Leap of Faith." It's not played to any extremes, either. Al simply doesn't believe because of what happened to his father. According to Al, the last thing his dying father said was to pray for him and that everything would work out. It didn't. [[spoiler:When Sam is nearly killed later on and lying there unconscious, Al doesn't hesitate to pray for his friend.]]
* {{Hologram}}: Al is one of these to Sam. He's in a room which projects an image of its contents back to Sam's brain except the official explanation is a vaguer way of saying "Sam's brain" that also allows him to be seen by animals and small children, a common form of GlamourFailure. The room's door is one of the trademark moments of the show, where a bright backlit doorway would open and Al would come in and out. This also meant that the entire world around Sam is a hologram to Al, not limited to what Sam could see, thus allowing him to see behind him, around doors or (as Al was wont to) ladies' locker rooms and restrooms.
* TheHomewardJourney
* HoodHopping: During the climax of one episode, Sam is trying to stop a woman from being murdered, and the taxi he's in gets caught in a traffic jam. Having no time to spare, he exits the cab and runs to the woman's apartment by leaping from car to car. To make things more awesome, at the time, Sam had leapt into Dr. Ruth Westheimer.
* HurtingHero: Sam. Let's see, his father lost the family farm and then died relatively young, his brother was killed in Vietnam and his sister married an abusive alcoholic. And being the kind of person he is, he feels guilty about all of it - particularly the farm and his sister. The trope is particularly evidenced in "The Leap Home, Part 1," where Sam tries to change his family's future and finds that it's not so easy to do.
* IdenticalGrandson:
** In two episodes Bakula plays Sam's father (under heavy makeup) in addition to playing Sam.
** A variation. While his great-grandfather, Captain John Beckett ''doesn't'' look like Sam in the Mirror, the genetic markers in his DNA are near-identical, which is theorised as being the reason why Sam could leap outside of his lifetime and end up in 1862.
* IJustWantToBeNormal: Though his goal is to get home, Sam genuinely loves having the opportunity to help people. However, in several episodes (such as "Catch A Falling Star"), Sam laments not having any semblance of a life.
* IJustWantToBeYou
** Usually played for laughs with Al to Sam. Often enough, Sam gets to be in the company of attractive women and Al complains that Sam wastes golden opportunities that he would gladly jump at.
** Played very seriously, though, in "The Leap Home, Part 1," where Sam laments being around his family but being unable to change their futures for the better.
-->'''Al:''' I'd give anything to see my father and my sister for a few days. Be able to talk with them again, laugh with them, tell 'em how much I love them. I'd give anything to have what you have, Sam. Anything.
** Made even more heartbreaking when you remember that Al's mother did a runner while he was young, his father went overseas so Al was sent to an orphanage and due to having Down Syndrome, Al's sister was committed to a mental institution. When his father returned and the family was reunited, he shortly afterwards discovered he had cancer and passed away, which meant Al and his sister were once again sent back to the orphanage and asylum. When Al ''finally'' was old enough to become the legal guardian of Trudy, it turns out that she'd contracted pneumonia and died, 2 years previously [[TraumaCongaLine and they never even bothered to tell him]].
* ImpossiblyTackyClothes: Al has a wardrobe that would make even [[DoctorWho The Sixth Doctor]] cringe, but at least it's justified by Al needing Sam to be able to spot him in a crowd if need be.
** The Mad Magazine parody of Quantum Leap suggested that the blue lighted effect of Sam leaping was actually caused by the sun hitting one of Al's outfits.
* IOweYouMyLife
** According to "The Leap Back", Al has saved Sam's life twenty-three times up to that point. It's because of that that Sam leaps to save him.
** From the preceding "Shock Theater":
--->'''Sam:''' Who are you?\\
'''Al:''' I'm Al. I'm your buddy. I gave you your first break. And you're the only person that believed in me when I gave up believing in myself. You brought me on this project.
* IncorruptiblePurePureness: Sam. Parodied in "The Leap Back," where the simo-leap exchanged some personality traits between Sam and Al. Al is suddenly far more chivalrous, which he can't stand.
-->'''Al:''' This isn't fair! Sam! A beautiful body like that, and I'm just thinkin' pure thoughts?! Dammit!
* InspirationallyDisadvantaged: Deconstructed with Dianna Quinna of "Private Dancer." While an excellent dancer and able to speak normally, she refuses to admit that her deafness hinders her and that she needs help, leading her to get into increasingly worse situations--she can't keep a job, she's virtually homeless, and towards the end of the episode, she's so desperate for money that she's coming dangerously close to her original fate--a life of prostitution and an eventual death from AIDS.
* ItGetsEasier: Sam gets told this after killing a murderous character in self-defense.
* JackKerouac: One episode featured Sam trying to convince a fictionalized portrayal of the writer to help a young girl in trouble with local gangs.
* {{Jerkass}}: In "Runaway," the leapee's big sister harasses Sam throughout the episode and gets a smug grin whenever he gets into trouble (usually her fault). After resolving the main issue of the episode, Sam doesn't leap out until he threatens the girl into being nicer to her brother (by dangling her over an old well).
* KickTheSonOfABitch: In "Camikazi Kid," the leapee's older sister is engaged to a seemingly nice guy that can get very abusive in private (and does regularly hit her in the original history). Sam gets the better of the guy and exposes him for what he is, which leads to the sister almost being assaulted. Sam responds by slugging the guy on the spot.
* LabPet: In "The Wrong Stuff," Sam leaps into a lab chimp in the space exploration lab, being prepared to go into space. His experimenter gets attached to him, and complains when he's transferred to helmet testing - which is basically "put a helmet on a chimp and bash its head with a giant hammer."
* LadykillerInLove: Al remains hopelessly in love with his first wife Beth, even several decades after she got remarried, believing he'd been killed in action (he was actually a POW). It's heavily implied the reason he was married several times and why his relationships never lasted long was that he was trying to fill the void left by Beth.
* LetMeTellYouAStory: In "Jimmy," Sam leaps into a mentally retarded man in the 1960s. Eventually he freaks out in frustration, since he's being treated like an idiot all day. Al interrupts him mid-rant: "There was this girl named Trudy..." Sam snaps at him that this is no time for another irrelevant, sleazy sex story -- but this time, the girl in question was Al's younger sister, who was also mentally retarded.
* LieToTheBeholder
* LukeIAmYourFather: [[spoiler:In the final part of "Trilogy", Sam and Al realize that Sam is the biological father of the focus character's daughter, conceived when he lept into the woman's fiancé during sex. However, she apparently never finds out, despite working for the Quantum Leap Project in the "fixed" timeline.]]
* MagneticHero: Sam.
* MakeWrongWhatOnceWentRight: The Evil Leaper.
* MandatoryTwistEnding: Only when the paranormal was involved, Or Was It?
* MaybeMagicMaybeMundane: Zoey reminds Alia that "We clawed our way out of ''Hell''" to get their evil leaping jobs. It's extremely vague on whether they were literally from Hell or not, but given the presence of other paranormal stuff in the series, the literal meaning is disturbingly plausible.
* MeaningfulName: In "Moments to Live," Sam gets kidnapped by a woman whose maiden name is [[{{Psycho}} Norma Bates]].
* MentalTimeTravel: Or at least it originally was...
* TheMirrorShowsYourTrueSelf: Inverted. Sam (and the viewer) sees the image of the person he's "leaped into" in mirrors- otherwise he looks like himself.
* MissionControl: Al and the rest of the Project.
* MisterSandmanSequence
* MisterSeahorse: The episode "8 1/2 Months" had Sam leap into a pregnant woman... and later on, he began to gain the symptoms of pregnancy, despite not ''really'' being pregnant. When Sam ultimately leaps out, [[spoiler: ''he's in the middle of giving birth''!]]
* TheMistress: Sam has to save one from suicide in his first leap into a woman.
* MoodWhiplash: The moments after many of Sam's leaps, especially if leaping from a very dramatic episode into a comedic one (or vice versa). "Oh, Boy!" Indeed.
* MoreThanMeetsTheEye: Al's character, when turning from a vulgar pervert to a heroic woobie.
* TheMovie: As of late 2010, under development by DonaldPBellisario.
* MultitaskedConversation: Sam and Al need to have these occasionally.
* MusicalEpisode: "Catch a Falling Star" sort of. The setting is a theater performing ''Literature/DonQuixote'' and the musical numbers are done in the context of performances/rehearsals. The last act is mostly composed of the final performance.
* MyGodWhatHaveIDone: In "The Leap Home, Part 2", [[spoiler:Sam saves Tom, but Maggie -- who Sam insisted on going the mission and survived in the original history -- is killed by a landmine]].
-->"I traded a life for a life!"
* MyGrandmaCanDoBetterThanYou: In the episode "Running for Honor," Sam leaps into a track runner, and fails to live up to the guy's previous performance:
-->'''Sam:''' ''(looking at his time)'' Is that good?\\
'''Coach:''' Yeah, that's great. If you're my grandmother!
* NakedInMink: In "Goodbye Norma Jean," Barbara tries on Marilyn's white fox coat, and a pair of her heels, and nothing else.
* NamedAfterSomebodyFamous
** Sam Beckett? As in Samuel Beckett? There might be something meaningful in that, but the best we can come up with is that he wasn't always sure why he was where he was, and "Dr. Vladimir Estragon" was too ridiculous.
** Internal to the series, Sam's full name is given as Samuel John Beckett, son of John Samuel Beckett. It seems like the elder was not intentionally invoking anything. Whether or not Bellisario was invoking anything for a laugh is another matter. There was definitely some monkey business behind his mother Thelma Louise Beckett...
** It gets lampshaded in a couple of episodes; in "Honeymoon Express", someone asks Al if Sam is related to the playwright, and Al responds "Not to my knowledge." In "Liberation", when Sam prepares "griddle cakes a'la Beckett", the leapee's daughter assumes that's who he's talking about, but Sam quickly covers by saying he meant "Mom Beckett, the famous chef".
** "Beckett" could also refer to becket, a nautical term referring to a loop of rope used to secure oars and boats. Could be a link to Sam's theories about time travel...
* NarratingThePresent: Sometimes Sam gives a past-tense narration in voiceover, although it's unclear when he would have found time to go back and write any of these events down. [[spoiler:Especially given the ending of the series.]] There's one particularly odd moment in the episode "Play It Again, Seymour:" Sam [[GotMeDoingIt catches himself using hard-boiled detective slang]] in the narration, and Sam-on-screen reacts to this, leading to the FridgeLogic conclusion that Sam just walks around mentally narrating his own life in the past tense.
* NewspaperDating: OncePerEpisode.
* NiceGuy: Sam, he's not quite an AllLovingHero but he friendly never takes advantage of women and well the fact of the matter is he always wants to help people he's around even when they annoy him.
** Underneath his cynical lecherous exterior, Al is very much one as well. He gets just as emotionally involved in each timeline as Sam does.
* NiceJobBreakingItHero: In "A Leap for Lisa," Sam inadvertently alters history so that a young Al stands trial for a rape/murder case and faces the death penalty. Originally Al didn't go to trial because he had an alibi thanks to the young nurse he had been with, who told his lawyer, who tells the court after she dies in a car accident. When Sam leaps in, he asks Lisa not to talk to anyone, meaning she takes the alibi to her grave and he does stand trial. In a mild subversion Al is okay with this, because it means [[NeverSpeakIllOfTheDead people won't be spreading rumors about Lisa over her grave]] (and presumably because he trusts Sam to fix things).
** And this ends up becoming ''completely'' subverted by the end [[spoiler: due to Lisa not dying]].
* NitroBoost: In "Camikazi Kid", Sam rigs up a nitro boost to win a drag race.
* NotSoDifferent: In "Deliver Us From Evil," Sam says as much while trying to talk Alia down from trying to shoot him.
-->"You can't kill me, Alia, because I know that somewhere inside of you there's a woman who feels the same things I do - the same loneliness, the same fear. I felt it the first time we touched; you felt it, too."
* NotThatKindOfDoctor: Averted. Sam is a medical doctor, just one of ''six'' doctorates he holds.
* NotableOriginalMusic: "Somewhere in the Night" (not to be confused with the Barry Manilow son of the same name) from "Piano Man" which was written and performed by Scott Bakula and was a minor hit in the 80's.
* NothingButHits: Just about any tune that you hear playing on the radio or performed in front of an audience will be an instantly recognizable tune from the era contemporary to the date of the leap. The same goes for movies and television.
* ObfuscatingDisability
** In "Blind Faith," Sam leaps into a blind concert pianist and has to keep up a pretense of blindness throughout the leap. The [[MyBelovedSmother mother]] of the leapee's girlfriend catches him during a moment in which he's let the pretense drop, and assumes that the leapee is a fraud; when she tries to expose him publicly, however, Sam has recently been blinded by an inconvenient flashbulb and passes her impromptu "test."
** Happens again in "Nowhere to Run," where Sam leaps into a Marine captain that had lost his legs in a landmine explosion. Similarly to the above, Sam can walk with no problem, but he has to pretend otherwise for obvious reasons. (He stops pretending, though, to beat-up an abusive orderly and later to save a man [[DrivenToSuicide from drowning himself]].)
* OffstageWaitingRoom: Literally. Averted in some later episodes (primarily from the fifth season), where viewers got to see Al interact with the leapees.
* OhCrap
** In "Last Dance Before An Execution," Sam leaps into a man on the electric chair, just before he's given a last-second stay of execution. Sam's OncePerEpisode "Oh boy" is understandably replaced with a panicked "Oh God."
** In "Mirror Image," Sam finds himself in a quiet town bar. As he settles in and gets his bearings, he looks in the mirror -- only to see ''himself''. "Oh boy" indeed.
** "[[HalloweenEpisode The Boogeyman]]," where Sam suddenly [[spoiler: puts his hand on Al...]] mere seconds before [[spoiler: another]] Al suddenly walks in stating that he hasn't been able to find Sam at all the entire episode.
* OmnidisciplinaryScientist: Among other disciplines Music, Medicine, Physics, Archeology, Ancient Languages, Chemistry, and Astronomy. Not to mention hobbies like [[{{Omniglot}} 7 modern languages.]] In the cases he doesn't know something, Al knows. [[spoiler:Though it's implied he didn't know all that when he started..]]
* OncePerEpisode
** A mirror-view of Sam's host [[spoiler:except for "Blood Moon," when Sam -- since he's leaped into [[RealAfterAll a vampire]] -- discovers he doesn't have a reflection.]]
** "Oh boy." Except for "Last Dance Before An Execution" (see OhCrap above).
** Also, Al walking through something [[spoiler: (with the exception of "The Leap Back," in which ''Al'' is the traveller and ''Sam'' is the hologram)]].
** Almost every episode ends with the start of Sam's next leap. There are exceptions, such as the premiere (when broken up into two parts), "M.I.A." (Al's final scene with Beth) or "Dr. Ruth" ([[spoiler: Dr. Ruth leaping out of the waiting room and being replaced by that vampire mentioned above]]).
* OneSteveLimit
** The trope was purposefully invoked in the finale, where Sam -- much to his surprise -- encounters a bartender named Albert, a man named Gooshie and a miner nicknamed Ziggy. This all plays into his discovery that there's something special about this leap.
** Also comes up in "Shock Theater," when Sam leaps into a man named Sam Bederman and Al points out that Sam can use his own name for once.
** Subverted in "What Price, Gloria?" where Sam hears his name called upon leaping in. He thinks he gets to use his name this time - only to realize that "Sam" is short for ''Samantha''.
* OnlyThePureOfHeart: Animals and children around the age of five and below see Sam as himself and can even see and hear Al. It's [[HandWave explained]] that they are in a sort of "Alpha State" that allows them to see through the "aura" Sam projects when he leaps into someone.
** In Reality, it is a case of RealLifeWritesThePlot since you can't tell a five year old to pretend that Al wasn't really there.
* OurTimeTravelIsDifferent: According to WordOfGod, not merely Sam's [[MentalTimeTravel mind/soul]], but his actual body displaces that of the "leapee," while that person's "physical aura" stays the same. This is a matter of some consternation both in and out of the show, as Sam's hosts are not always the same size as him... [[spoiler: most notably in "Nowhere To Run," where Sam leaps into an amputee and ''actually stands up despite having nothing below the knee''. In one case his host wasn't even the same species -- in "The Wrong Stuff" Sam leaps into a ''chimp''.]] It becomes very important in "Trilogy", [[spoiler: as in the second part Sam leaps into a man having sex with his fiancée, meaning that the daughter who appears in the third part is actually his.]]
* OurVampiresAreDifferent: A group of...eccentric people in England call themselves vampires and make human sacrifices (and drink their blood) to the "Blood Moon" and wear false, vampire teeth. [[spoiler:Turns out at least some real vampires may exist, as Sam cannot see a reflection in a mirror.]]
* PantyShot: Teresa in "Double Identity."
* ParanormalEpisode: The episode "The Boogieman". [[http://quantumleap.wikia.com/wiki/The_Boogieman_%28episode%29 The episode]] apparently has Sam going up against the Devil himself. However, it might have been AllJustADream.
* PeggySue
** "The Leap Home, Part 1"
** Al by proxy in "M.I.A.".
* PercussiveMaintenance: Al often smacks Ziggy's portable terminal when trying to retrieve information.
* PowersThatBe: Sam thinks that they are controlling his time travel. [[spoiler:Actually, Sam himself is doing it subconsciously. God tells him so in the last episode.]]
* PrettyInMink: In "Goodbye Norma Jean," Marilyn has a few furs shown: a white fox wrap, a white fox coat, and a white mink jacket.
* ProWrestlingEpisode: "Heart of a Champion."
* TheProfessor
* ProphecyTwist: In "Nowhere to Run," Sam's main mission to prevent a disabled veteran from killing himself, but he also has to ensure another part of history plays out. According to Al, the amputee Sam leaped into had a son (who will save a lot of lives during a Gulf War battle), and he has to ensure he will be born. [[spoiler:They initially think they have to repair the amputee's rocky marriage, but it turns out they didn't have to do anything. The mother turns out to be the nurse that Sam met at the start of the episode. Al acknowledges that he never bothered to check the mother's name.]]
* ProsceniumReveal: On more than one occasion, Sam leaps into a strange situation, only to discover that he's an actor in a play/on a sound stage.
* ProWrestlingIsReal: In one episode in which Sam leaps into the body of a wrestler playing an Evil Russian, it's confidently declared that wrestling actually is staged -- except for the title matches, and Sam and his partner's refusal to take a dive in a tag-team title match is the main conflict of the episode.
* RandomTransportation: The series featured Sam Beckett leaping at various points in history to SetRightWhatOnceWentWrong. He never knows what time period or into which person he'll Leap into next. A hint of this is almost always TheStinger for a given episode. The leaps generally occurred within the U.S. and stayed within Sam's lifetime. Though special circumstances have seen these rules broken at least once.
* ResignedToTheCall
** In "Catch a Falling Star," Sam encounters an old crush and the leap turns very personal. He even openly considers not "setting right what once went wrong" (in this case, saving a {{Jerkass}} [[DepartmentOfRedundancyDepartment actor]]) to avoid leaping anymore. Obviously, he gets over it and the following exchange echoes the trope (as well as further [[ShoutOut shouting out]] to ''Literature/DonQuixote''):
-->'''Al:''' Are you gonna be all right?
-->'''Sam:''' What matter wounds to the body of a knight-errant, for each time he falls, he shall rise again and woe to the wicked! Al?
-->'''Al:''' Here, your grace.
-->'''Sam:''' My armor, my sword!
-->'''Al:''' More misadventures?
-->'''Sam:''' Adventures, old friend.
** A very sad example in [[spoiler:the finale. "Home. I'd like to go home, but I can't, can I? I've got a wrong to put right for Al."]]
* RetroactivePrecognition
* RevolversAreJustBetter: In "MIA," when Sam leaps in, he cowers in the middle of the gunfight he's caught up in. When it's revealed that he's a male cop in drag and not a woman, his partner asks him if his pistol jammed again. One of the other cops tells him "Get a revolver, Jake. You'll live longer."
* RippleEffectIndicator
** While Al would usually just tell Sam what's changed, one episode featured Al being outright replaced because of Sam's actions during a Leap into Al in his younger days [[spoiler:because in the new timeline, Al ''died in the gas chamber'']].
** During "Honeymoon Express," Al is at a Congressional oversight trial and funding for the Project is in danger. In the past, Sam is helping the leapee's new wife study for her legal exams. He corrects her on a key fact, which she said getting wrong could've caused her to fail and damaged her career. Back in the present, Al (and the audience) sees the official leading the charge to cut off the funding replaced by an older version of the woman, who grants the Project further funding.
* RippleEffectProofMemory: There are times when Sam explicitly remembers how history originally played out even after he changed it.
** In "Rebel Without a Clue," he remembers that [[spoiler:Tom]] originally died, but that he "got him back."
** In "Honeymoon Express," history actually changes around Al with only him noticing the difference.
** The end of "Deliver Us From Evil," resets everything to before Alia leaped in, which accounts for two days. Sam and Al remember everything that happened (and their counterparts would as well), but Frank and no one else from that time period are any the wiser.
* RubberBandHistory: The episode where Sam saves Kennedy from being assassinated... [[spoiler:''Jackie'' Kennedy]] -- or saves Marilyn Monroe from overdosing... just long enough to make ''The Misfits''.
* RunningGag: Sam says "Al" only for the person he's with to say "I'll what?"
* SanDimasTime: In effect from the moment Ziggy finds where and when Sam's leaped.
* TheScottishTrope
** The third season's HalloweenEpisode, in which Sam encounters the devil himself [[spoiler:posing as Al]], is believed to be cursed, causing equipment malfunctions ([=VCRs=], TV stations, ...) and even mentioning the episode title is believed to cause trouble and hence frowned upon. Plus during two separate airings in California, two strong earthquakes occurred.
** The trope itself is invoked in "Future Boy," where Moe Stein chastises Sam for saying "[=MacBeth=]" as he considers it bad luck.
* SequelHook: "Deliver Us From Evil."
-->'''Sam:''' Where's Alia?\\
'''Al:''' She's... gone.\\
'''Sam:''' Alia's not gone, Al. Alia's not gone. ''(leaps out)''
* SerialSpouse: Al.
* SeriesFauxnale: "Mirror Image" was written and filmed as a ''season'' finale. When the series was cancelled afterwards, some last-minute editing was performed to ensure the series would have some kind of an ending. They didn't even manage to spell Sam's last name right, stating "Dr. Becket [[spoiler: never returned home]]"
* ShoutOut
** In "Another Mother," the leapee's oldest daughter doesn't want to miss that night's episode of ''MagnumPI''.
*** Unfortunately, this nixed plans for an episode where Sam leaped into Magnum (Don Bellisario had produced both shows).
** The "Dean Stockwell" ActorAllusion from "Animal Frat" is also a nod to ''Film/BackToSchool'' (the dean having a PunnyName).
** In one episode, Sam refers to the skintight suit worn inside the Quantum Leap Accelerator as a [[http://en.wikipedia.org/wiki/Enrico_Fermi "Fermi Suit"]].
* ShowWithinAShow: Several, actually, but arguably the most important was ''Time Patrol'', from which a young Sam got his string theory of time travel.
* SignificantReferenceDate: In "The Leap Back," Al mentions that when he entered the imaging chamber it was Sept 18th, 1999. The episode originally aired on Sept 18th, 1991.
* SixIsNine: In "The Boogeyman," Sam leaps into the body of a horror writer whose street address is 966. Near the climax, [[spoiler:the 9 flips upside down to reveal that the devil is amongst them]].
* SkepticismFailure: Somewhat mitigated by the fact that this series [[BellisariosMaxim named another trope]].
* SleepingWithTheBoss: When for the first time Sam leaps into a woman, his task of the episode is to keep a fellow secretary from committing suicide. The other secretary thinks that her boss is going to leave his wife for her; the wife informs the secretary in no uncertain terms that she's OK with her husband fooling around but she will not under any circumstances allow a divorce. It's also implied that she is the boss's second wife, and he met her when she was his secretary. When the secretary learns this, she tries to jump off a building but Sam talks her down.
* SmiteMeOhMightySmiter: After three and a half seasons, God owes Sam at least one favor. In "A Single Drop of Rain," Sam demands that He pay up. [[spoiler: He does.]]
* SpeechImpediment: "Trilogy, Part 2" has Sam adopting the stutter of the man that he leaped into for nearly the ''entire'' episode.
* SpiritAdvisor
* SplitPersonality: Happens to Sam a few times, where his mind would merge with a leapee's. Sam would subsequently pick up their habits or knowledge, and sometimes act as they would without a second thought.
** "Shock Theater" really exploited this. After Sam is given electro-shock, he keeps shifting to different people he's leapt into -- Samantha Stormer ("What Price, Gloria?"), Jesse Tyler ("The Color of Truth"), Herman "Magic" Williams ("The Leap Home, Part 2"), Tom Stratton ("Genesis"), Kid Cody ("The Right Hand of God"), and Jimmy [=LaMotta=] ("Jimmy").
** In "Return of the Evil Leaper", Sam is influenced by Arnold Watkins, The Midnight Marauder and suffer from bouts of ChronicHeroSyndrome.
** A particularly dark example in "Lee Harvey Oswald," where Sam leaps into the infamous assassin. Throughout the two-parter, Sam feels Oswald's influence and a SplitPersonalityTakeover slowly ensues. [[spoiler:They just barely avoid GollumMadeMeDoIt]]. This episode also shows the reverse, where Sam's personality briefly influences Oswald.
* TakeThat
** The "Lee Harvey Oswald" two-parter was this to Oliver Stone's ''JFK''. Bellisario (who had actually known the real-life Oswald while in the U.S. Marines) considered the movie "crap" and did the two-parter to show [[WhoShotJFK another take on the real-life event]].
** In "The Leap Back", after Sam has to deal with Ziggy, he grumbles "Why did I have to give him Barbara Streisand's ego?"
* TeenPregnancy: Sam once leaps into a pregnant girl -- and barely makes it out before the birth.
* TemporaryBlindness: "Blind Faith"
* ThanatosGambit: [[spoiler:In the final part of "Trilogy", Abigail is accused of murdering the woman who's been harassing her for years (said woman having been convinced that Abby murdered her daughter and husband). Sam, as her lawyer, eventually realizes that the dead woman killed herself with the intent of framing Abigail and getting "revenge", having long since crossed the DespairEventHorizon.]]
* ThrillerOnTheExpress: "Honeymoon Express."
* TimeShiftedActor: Happens all over the place in the three-parter "Trilogy", where Sam helps out a woman named Abigail Fuller at ages 10, 21, and 35, and his leapees each appear in the preceding part. Following this trope more closely, Abigail is played by one actress at age 10 and another at ages 21 and 35, while the first actress is in third episode as [[IdenticalGrandson her daughter Sammy Jo]].
* TimeTravel
* TimeyWimeyBall
* TomatoInTheMirror: Turns out that in the Leap 'verse, [[spoiler:vampires are apparently real]]. As well as [[spoiler:ghosts, aliens, bigfoot and a few other supposedly mythical creatures]].
** But [[WhoShotJFK Lee Harvey Oswald acted alone]], and the [[http://en.wikipedia.org/wiki/Jack_Ruby weirdos]] who contributed to his mythology were just weirdos.
* TwentyMinutesIntoTheFuture: The series was initially vague on when the present-day was (though it couldn't be that far ahead due to Sam leaping within his own lifetime). Eventually, the series set the year to 1999.
* TwoRoadsBeforeYou: In "Mirror Image," [[spoiler:Sam is essentially told that he can either continue leaping (where he will face even tougher challenges) or go home. Sam chooses to leap so that he can save Al and Beth's marriage.]]
* UnsettlingGenderReveal: Invoked in "What Price, Gloria?" Sam has lept into Samantha, a gorgeous blonde. One of the hassles he faces is Buddy Wright, a jerk of an executive with a penchant for sexual harassment. Before leaping out, Sam makes Buddy squirm by convincing him that he's lusting after a man. [[KickTheSonOfABitch Sam then decks him for good measure.]]
* UnstuckInTime
* UnusualEuphemism: "Nozzle" for anyone Al doesn't approve of.
* VerySpecialEpisode: "Raped."
* VoodooShark: That "physical aura" thing.
* WalkingTheEarth: But substitute "Timeline" for "Earth".
* WardensAreEvil: The final episode of the "Evil Leaper" saga has Sam leap into an inmate at a women's prison. Having convinced the aforementioned evil leaper to make a HeelFaceTurn, both are pursued by a replacement evil leaper who leaps into the prison warden and thus effectively having her acting in this trope. Then, once she is killed and the original warden returned in her place, he is revealed as being responsible for a murder for which another inmate had been accused.
* WeWillMeetAgain: In "Deliver Us From Evil," as Alia is being forcibly leaped out, Zoe vows they will find Sam again one day.
* WeirdnessSearchAndRescue: It was implied that [[MysteriousBacker some conscious force]] (possibly even God) was guiding Sam' jumps to ensure that he did the most good. This was a {{deconstruction}} since this mysterious guide was [[UnknownCharacter never actually seen or had a voice]] (although they met someone who ''might'' have been them). It only made itself known by directing events like an actual deity would and, of course, when it did more or less directly interact with the main character, it was a total MindScrew.
* WideEyedIdealist: Sam.
* WhamLine
** In the episode "So Help Me God," Sam leaps into a laywer in the deep south during the 1950's, defending a black woman accused of murdering a white man. She openly admits she killed him and Sam spends the entire episode trying to prove that it was just self-defense or an accident[[note]]Sam's reasoning being why else would he be there if it was just to make sure she was convicted? That was what had happened in the original timeline.[[/note]] Eventually, he is able to get the sole witness, the victim's mother (who is mentally... distant), to testify. She recounts the incident before saying [[spoiler:[[OffingTheOffspring "That's when I picked up the shotgun..."]]]]
** An example from "The Leap Home, Part 2" doesn't really affect the plot (as it comes at the end), but is notable in how it affected the fandom's experience and what the possible implications mean. [[spoiler:Tom celebrates surviving the day it was alleged he would die on, telling Sam, "And it's all thanks to you, little brother."]]
** The last line from "Lee Harvey Oswald" changes a DownerEnding into a [[BittersweetEnding bittersweet one.]] "Your Swiss cheesed mind probably doesn't remember, but the first time, [[spoiler:Oswald killed Jackie, too.]]"
* WhamShot: [[spoiler:Sam's lack-of-reflection at the end of "Blood Moon".]]
* WhatHappenedToTheMouse: Sometimes, Sam leaps out before Al can tell him (or the audience) about the leapee's life post-episode. This is often given a HandWave with a line like "Everything turns out okay".
* WhereAreTheyNowEpilogue
** The one that was infamously tacked on to the final episode.
** Also usually happens at the end of an episode, with Al telling Sam how the positive effects of the leap have helped the people in question (or, in at least one case, not).
* WhereDaWhiteWomenAt: In "Black on White on Fire," Sam leapt into Ray, a black medical student in the 60's who was engaged to a white woman. Neither of their families approved (although Ray's mother was more concerned about Susan's safety -- the episode took place during the Watts riots -- than disapproval of her son dating a white woman.)
* WhoShotJFK: According to this show, [[TheUntwist Lee Harvey Oswald. All by himself.]]
** This is actually because Bellisario served with Oswald in the Marine Corps (and those segments of the episode feature a character based on him), and believed him to be fully capable of taking the shot on his own.
* WifeBasherBasher: Sam becomes this in "Camikaze Kid", where the leapee's sister is in an abusive relationship. At the end of the episode, after the guy gets rough with her in public and punched down by Sam (not to mention [[DisproportionateRetribution trying to run Sam over after losing to him in a car race]]), his bully friends [[EvenEvilHasStandards walk out on him]].
* WoobieOfTheWeek: Along with WalkingTheEarth, the show's premise.
* WorkingOnTheChainGang: Sam leapt into a prisoner who was subject to this. He was there to establish another prisoner's innocence and expose the fact that the warden had been keeping them there for too long (Sam's character was only supposed to be serving a nine-month sentence but had been there for years).
* WrongGenreSavvy: In "The Color of Truth", where Sam keeps forgetting that given the rampant racism prevalent in the Deep South during the late 1950's, a black man doing minor things like sitting at a diner counter and drinking from a fountain were ''SeriousBusiness''.
* YearOutsideHourInside: According to the pilot, whereas time in-between leaps is instantaneous for Sam, it can take days or weeks for him to arrive somewhere, plus some time for the Project to get a lock on him once he gets there, although that part appears to happen in real time. This wasn't touched on much in the rest of the series.
** This is possibly overlooked in the episode where the funding the threatened, as someone makes the claim there's no evidence that Sam is leaping, because Sam's body is still there as far as anyone can tell, and it's just as likely that he's simply gone insane and taking on random personalities. While that might explain his behavior when his body is there, it doesn't explain how that body vanishes for days at a time and reappears out of thin air once Sam gets somewhere and displaces a person. OTOH, this was probably just an excuse to make the project "prove it" and alter the past in the way the government wanted, and no one actually disbelieved it was happening.
* YetAnotherChristmasCarol: Zig-Zagged.
* YouCanSeeMe: Originally, only Sam could see Al, but this was extended to young children, animals and the mentally disabled.
** In "Another Mother" and "A Tale of Two Sweeties," the youngest children of the leapees sees both Al and Sam.
** In "The Leap Home, Part 2", [[spoiler:after being fatally wounded, Maggie looks up at Al before she dies]]. Al has this reaction.
** In "Shock Theater," Tibby (a young adult that's a patient) can see both Sam and Al, as well. Some of the other patients can at least see Al, also.
** In "A Little Miracle," Blake is able to see Al because his neurons and mesons are very close to Sam's.
** In "It's a Wonderful Leap", Angela can see and communicate with Al because she's an angel.
** In "The Color Of Truth", Al is able to save Melanie from the tracks by shouting at her loud enough, though she believes that he is her dead husband.
* YouCantFightFate: The painful lesson of "The Leap Home, Part 1," where Sam tries to prevent his father from dying early, his brother Tom being killed in Vietnam the next year and his sister Katie from marrying an abusive alcoholic. As Al tells Sam, he's not changing their futures; he's only making their present miserable. [[spoiler:Partially subverted in the next episode, where Sam leaps into Vietnam and manages to save Tom's life.]]
* YouCantGoHomeAgain: Played painfully straight in "The Leap Home, Part 1." Sam is thrilled to be back in his hometown as his sixteen-year-old self, but his failing efforts to prevent the tragedies that befell his family terrify them and sends him into a HeroicBSOD.
* YouLookFamiliar
** Carolyn Seymour plays Priscilla in "A Portrait for Troian" and evil hologram Zoe in Season 5. The series can actually get around the similarity in this instance because (aside for brief moments) Sam and Al never see what Zoe looks like.
** "Mirror Image" is partially built on this trope, with Sam encountering people that look like ones from previous leaps -- John D'Aquino (Tonchi for Frank) and Richard Herd (Ziggy for Moe Stein). Notably, while Bruce [=McGill=] played both Weird Ernie and Bartender Al, Sam doesn't notice any familiarity.
** Willie Garson appears in "Play It Again, Seymour" as the titular Seymour and in "Lee Harvey Oswald" as Oswald.
** Olivia Burnette plays the older daughter of Sam's housewife leapee in "Another Mother" and Sam's sister Katie in "The Leap Home".
** Charles Rocket plays Michael Blake in "A Little Miracle" and Commander Riker in "A Leap for Lisa".
* YouWouldMakeAGreatModel: In "Miss Deep South", an unscrupulous photographer talks a beauty pageant contestant into a "tasteful" photo shoot by promising that he can get her modeling work. Then he gets her drunk and persuades her to take off more clothing, reassuring, "I won't shoot anything that will embarrass you." The photos show up in a nudie calendar a few months later, ruining the girl's career (unless Sam can stop it from happening).
** YoureJustJealous: The girl's answer to Sam, when he was trying to stop her.
* YouWouldntHitAGuyWithGlasses: In "The Cam-ikazi Kid", Sam leaps into a dorky teenager who is harassed by bullies. He protests, "You can't pants a guy with glasses!" The bully replies, "What glasses?", takes the glasses, and pantses him anyway.
* YoungFutureFamousPeople
** In "It's a Wonderful Leap", Sam is driving around a man and his son, and tells them some vague bits of information about New York's future in real estate. At the end of the cab ride, Sam finds out the passenger was [[spoiler:a young Donald Trump]].
** There've also been episodes in which he meets a young Creator/StephenKing and Martin Luther King Jr's great-great-grandfather.
** In others, he shows young Music/MichaelJackson moonwalking or gives young SylvesterStallone boxing tips.
** In "How the Tess Was Won," the whole point of the leap turns out to be giving a young BuddyHolly the inspiration for the song "Peggy Sue."
** Sam leaps into a young ElvisPresley. In the same episode, we also see a young saxophone player going by the name of [[BillClinton Billy C]].
** At a Jewish wedding, Sam gets up to save a man from choking by with the Heimlich maneuver. Immediately afterwards, a woman rushes up to lead him away, asking "Are you all right, Dr. Heimlich?"

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