Harry Harrison (1925-2012; born Henry Maxwell Dempsey) was a science fiction writer.

He is best known for his humorous SF, which includes ''Literature/TheStainlessSteelRat'' series, the ''Literature/BillTheGalacticHero'' series, and the stand-alone novels ''Literature/TheTechnicolorTimeMachine'' and ''Star Smashers of the Galaxy Rangers''.

He has also written serious SF, including ''Literature/MakeRoomMakeRoom'', which inspired the film ''Film/SoylentGreen'' (although the film's most famous plot element was not in the book); the ''Literature/{{Deathworld}}'' trilogy; the ''Literature/ToTheStars'' trilogy; and the ''Literature/WestOfEden'' trilogy.
!!Works by Harry Harrison with their own trope pages include:
* ''Literature/BillTheGalacticHero'' series
* ''Literature/{{Deathworld}}'' series
* ''Literature/TheHammerAndTheCross'' trilogy
* ''Literature/MakeRoomMakeRoom''
* ''Literature/TheStainlessSteelRat'' series
* ''Literature/TheTechnicolorTimeMachine''
* ''Literature/ToTheStars'' trilogy
* ''Literature/TheTuringOption'' (with Marvin Minksy)
* ''Literature/WestOfEden'' trilogy
!!Other works by Harry Harrison provide examples of:

* AlternateHistory
** In ''A Transatlantic Tunnel, Hurrah!'', America [[AmericaIsStillAColony lost the War of Independence]] and remained part of the British Empire. (Also, an earlier military defeat changed Spanish history enough that Christopher Columbus couldn't get funding, leaving American to be discovered by John Cabot in 1497.)
** The ''Stars & Stripes'' series envisions the Trent incident from the American civil war blowing up into a full-scale war between the United States and the British Empire. A navigational error brings the Confederacy in on the Union side, ending the civil war, and resulting in the British getting their asses handed to them by Generals Lee, Grant, Sherman, and Stonewall Jackson.
* AmericaIsStillAColony: In ''Tunnel Through the Deeps'', due to the fact it was John Cabot, not UsefulNotes/ChristopherColumbus, who discovered North America, Spain was also never unified and unable to fund Columbus. This lead to a scenario where the revolutionary war was lost and UsefulNotes/GeorgeWashington was shot as a traitor. The main character is a descendant of Washington who feels tarred by his family's bad reputation whilst working on a transatlantic tunnel between the British Isles and the Northern American colonies.
* CarCushion: Played with in "Portrait of the Artist", in which [[spoiler:a comic book artist, who has just lost his job to a machine, creates a suicide note in comic-book form that ends with a depiction of him jumping off his publisher's office building and landing on a car. After he commits suicide in the manner depicted, his ex-boss's only reaction is remark that he landed on the wrong car]].
* ChildSoldiers: In "War With the Robots", the command staff are all teenagers as anyone older lacks the reflexes and flexibility of mind needed to fight the war. They retire after four or five years.
* GenerationShips: In ''Captive Universe'', a generation ship with a seamless environment is launched; by design the highly repressive, extremely stable Aztec cities onboard believe themselves to be in an inaccessible river valley. The ship tenders are if anything more rigid and religious: an extraordinary asceticism rules their lives and repairs are sacred rituals.
* HideousHangoverCure: The Drive-Right pill, which appears in more than one series, is a small round pill that will make you absolutely stone cold sober seconds after swallowing it... it's completely black except for a skull and crossbones on each side. Unfortunately it's rather unpleasant to take.
* HumansThroughAlienEyes: In "The Streets of Ashkelon", a human missionary converts an alien culture to UsefulNotes/{{Christianity}}. [[spoiler:The aliens then try to initiate the millennium of the missionary's message by crucifying him and waiting for him to rise on the third day.]]
* ImprobableAge: Justified in "War With the Robots"; the command staff are all teenagers as anyone older lacks the reflexes and flexibility of mind needed to plot strategy in the fast-paced war. They retire after four or five years.
* JobStealingRobot: "Portrait of the Artist" is about a comic strip artist who loses his job to a machine.
* TheLastOfTheseIsNotLikeTheOthers: In ''Star Smashers of the Galaxy Rangers'', John claims to be trained in:
-->...spying, warfare, intelligence, brain surgery, proctoscopy, codes and ciphers, blue-ribbon cooking, and murder.
* MercurialBase
* MobileSuitHuman: The inverse (a human concealed inside a robotic alien suit) happens often in Harry Harrison sci-fi, such as ''Repairman'' and ''Star Smashers of the Galaxy Rangers''.
* RobotWar: In "War With the Robots", the human occupants of a command headquarters are forced out of their underground base by robot attack, leaving it to be manned by their own robots. On reaching the surface they find the enemy command staff living as farmers on the war-torn battlefield above -- it turns out the robots on both sides find they can conduct the war more efficiently once humans are out of the way. The protagonist is deeply miffed.
* SpaceOpera: Parodied in ''Star Smashers of the Galaxy Rangers''.
* {{Unobtainium}}: The Golden Age SF spoof novel ''Star Smashers of the Galaxy Rangers'' features Cheddite (a fuel created from cheese). In another scene the heroes' 747 jet is turned into a spacecraft by means of windows armored with ''armolite'', vacuum insulation with ''insulite'', fuel tanks filled with ''combustite'', guns firing pellets of ''destructite'', batteries replaced with ''capacitite'' and a space-warp drive powered by ''warpite''.
* WhatIsThisThingYouCallLove: Satirized in "The Robot Who Wanted To Know". Sophisticated robot librarians designed to think independently often focus on a particular area of interest; Filer 13B-445K's interest is human concepts of love and romance. After reading up on it he wants to experience it personally and goes to some lengths to disguise himself as an attractive man for a costume ball. Naturally the busty heroine ends up falling for him and is outraged to discover his mechanical identity. He responds by [[LogicBomb nosediving into a paradox spiral and self-destructing]]. Workers examining the wreck later find a malfunction in the central pump and joke that "you could almost say he died of a broken heart".
* YouAreInCommandNow: In ''Spaceship Medic'', the eponymous medic ends up in charge after all the rest of the ship's officers are wiped out by a meteorite hitting the bridge (then has some adventures, saves the day, and goes back to being a doctor).