[[caption-width-right:350:Buster [[ReadTheFreakingManual reads the manual]] and tries out a [[MasterOfDisguise disguise]].]]

->''"While employed as a moving picture operator in a small town theater he was also studying to be a detective."''
-->-- '''Intertitle'''

This 1924 Creator/BusterKeaton film is an oddity -- longer than the average comedy short but not long enough to be a feature film, it's an AffectionateParody of the 1922 Creator/JohnBarrymore film ''Theatre/SherlockHolmes'', with Buster playing a movie projectionist and would-be sleuth. Framed for theft by a romantic rival and unable to prove his innocence, the protagonist goes back to the movie theater where he works, dozes off next to the projector, and dreams that he is Sherlock, Jr., the World's Greatest Detective.

Today, the movie is best remembered for the sequence in which the projectionist's ghostly dream avatar walks into the movie screen, where a series of jump cuts places him in embarrassing and dangerous situations. These scenes may have inspired or influenced Creator/WoodyAllen's ''Film/ThePurpleRoseOfCairo'' (in which a character from a Depression-era romantic comedy steps off the screen into the real world), the Creator/ArnoldSchwarzenegger film ''Film/LastActionHero'' (in which a young boy enters an action movie and brings the hero into reality), and the [[WesternAnimation/LooneyTunes Merrie Melodies]] short "WesternAnimation/DuckAmuck" (in which WesternAnimation/DaffyDuck is tormented by an animator).

The dream concept gave Keaton leeway to push the boundaries of his filmmaking. He takes the opportunity to recreate some classic vaudeville stunts, including one startling moment when he appears to jump through another actor's torso. The high-society setting of the dream also gave him an excuse to use more luxurious sets and costumes than was usual in his films.

This film is available on [[https://www.youtube.com/watch?v=cC1aD7e4ZHs YouTube]].
!! ''Sherlock Jr.'' provides examples of:
* AddedAlliterativeAppeal: A title card describes Sherlock Jr. as a "crime-crushing criminologist."
* AffectionateParody: Buster's dapper detective is based on Creator/JohnBarrymore's portrayal of Franchise/SherlockHolmes in [[Theatre/SherlockHolmes his eponymous 1922 film.]]
* AllJustADream: Most of the second half of the film is Buster's dream of being a famous detective.
* BabiesEverAfter: The end of ''Hearts and Pearls'', the film within the film.
* BadGuysPlayPool: And in this case they set up a death trap by switching out the #13 ball with a fake ball that is actually a bomb.
* BananaPeel: causes Keaton to do an enormous pratfall
* BeyondTheImpossible: Sherlock Jr. appears to jump ''through'' both his disguised assistant and the wall behind him, and Gillette spins around and walks away immediately afterward. This, like the quick change, is a stunt Keaton learned in vaudeville, but unlike the quick change this gag is not fully explained within the film.
* BrickJoke: See ChekhovsGun below.
* ButYouWereThereAndYouAndYou: All of the characters in the framing story appear in the dream sequence in analogous roles.
* TheButlerDidIt: In Buster's dream, the butler is in on the robbery.
* ChangingClothesIsAFreeAction: The hero performs a quick change on camera by literally jumping through a hoop, but we watch him set it up in advance (though most first-time viewers probably won't realize what they're seeing until the payoff).
* ChaseScene: A long, elaborate one as Buster and his girl flee the villains' hideout.
* ChekhovsGun: The explosive #13 pool ball, which Buster switches out for the real ball, then puts in his pocket and forgets--until the climax of the chase, when he hurls it at the pursuers' car, which blows up.
* ClearTheirName: While Buster cracks the case in his dream, in real life his girl succeeds in discovering who stole her father's watch.
* DeadFootLeadfoot: Sorta -- the hero hops onto the handlebars of a motorcycle. Shortly afterward the driver (still alive) falls off, but the 'cycle keeps going. Keaton rides a speeding motorcycle while perched on the handlebars for this sequence, without realizing that the driver fell off until shortly before the crash.
* DeathTrap: The villains rig a billiards room with an exploding pool ball, a poisoned drink, and a falling ax controlled by a hidden trigger.
* DoubleTake: Sherlock Jr. performs an epic take when he realizes he's riding the handlebars of a driverless motorcycle.
* DreamSequence: Most of the film.
* DynamicEntry: Sherlock Jr. arrives at the shack where the girl is being held captive, flying feet-first through a window.
* FadeToBlack: At the end, the hero watches the [[ShowWithinAShow movie within the movie]] for tips on how to treat his sweetheart. Imitating the onscreen action, he gives the girl a ring, kisses her ... and is left scratching his head in bewilderment when a fade to black is followed by BabiesEverAfter.
* {{Frameup}}: The projectionist takes the fall for the local sheik's misdeed.
* FramingDevice: The "waking life" sequences that introduce the characters and scenario of the hero's dream, and to which we return for the film's end.
* IHaveYouNowMyPretty: The unpleasant leer that one of the mooks gives Buster's girl is clearly meant to be this.
* ImprobableAimingSkills: The various trick shots that Buster takes to sink all the other pool balls without ever hitting #13, climaxing in bending another ball around #13 and then causing the cue ball to skip over #13 completely. [[DoingItForTheArt It took Keaton five days of shooting to make all the shots.]]
* IncrediblyObviousTail: When the book said "Shadow your man closely," it didn't mean ''that'' [[http://www.youtube.com/watch?v=Ech3Syf41LE closely]].
* InstantCostumeChange: The vaudeville quick-change gag jumping out the window.
* TheKlutz: In both his waking and dream life, the hero has a tendency to walk into doors.
* LiteralMinded: "Shadow your man closely."
* LoveTriangle: The Projectionist, the Girl, and the Local Sheik
* MadeOfExplodium: The film doesn't say exactly what the 13 ball is made of, but dropping it is a bad idea.
* MasterOfDisguise: Subverted with the hero in both waking and dream life.
** Played straight with Gillette.
* MatchCut: The highlight of the movie is the sequence where the film-within-a-film keeps cutting to different scenes, much to Buster's consternation. In one scene, he's squatting to sit on a bench in a courtyard, when the film cuts to a street scene, leaving Buster to fall on his butt on the sidewalk.
* MirrorRoutine: A variation -- Sherlock Jr. appears to be standing before a full-length mirror, then walks through what is actually a doorway between two identical rooms.
* PinballProjectile: The hero performs amazing trick shots while playing pool with the bad guys in order to '''miss''' (sometimes just barely) the 13 ball.
** And then he actually hits the 13 ball... which doesn't explode, because he's switched it back with the real one.
* PoisonedChaliceSwitcheroo
* ThePratfall: when Keaton slips on a BananaPeel.
* PunchedAcrossTheRoom: Possibly justified, since the assailant had just been flung off a speeding motorcycle.
* RailroadTracksOfDoom
* ReadTheFreakingManual: Subverted -- the projectionist [[LiteralMinded faithfully]] [[IncrediblyObviousTail obeys]] the dictates of ''How To Be a Detective.''
* ShoutOut: In the dream, Buster's assistant is named "Gillette". William Gillette was the author and star of the long-running and wildly popular ''Theatre/SherlockHolmes'' stage play.
* ShowWithinAShow: The hero falls asleep watching a melodramatic film, ''Hearts and Pearls; or, The Lounge Lizard's Lost Love'', which influences his dream.
* SomebodySetUpUsTheBomb: The bad guys' exploding pool ball is turned against them during the climactic chase.
* StealthPun: The title card introducing Sherlock Jr.'s helper. To get the whole joke, you need to know that [[spoiler: Gillette, Gem, and Ever-Ready are brands of razor blades, and the first actor to play Sherlock Holmes on the stage was named William Gillette]].
-->His assistant --
-->A Gem who was Ever-Ready in a bad scrape.
* StickySituation: Buster gets tangled up with a sheet of flypaper while sweeping up the theater.
* TakeTheWheel: Sherlock Jr. briefly hands the steering wheel off to the girl so he can throw the exploding pool ball at his pursuers.
* ThirteenIsUnlucky: The exploding pool ball.
* TrappedInTVLand: The projectionst dreams that he walks through the theater and into the movie screen, where he becomes part of the film.
* WhatHappenedToTheMouse: What happened to the detective that the thugs had hanging in their hideout?