Science fiction encompasses quite a number of subgenres and themes. More often than not, a novel, short story, movie, or TV show will straddle multiple subgenres and deal with more than one theme at once. This contributes to a rich, thoroughly entertaining, and highly intuitive genre of fiction. What follows is a loosely categorised (though increasingly comprehensive) guide to the subgenres and themes of science fiction. Only works of literature are given as examples.

Subgenres

This genre takes historical events of the past and asks “what if …”, often changing the way history developed as we know it today. Some alternate history includes definite science fiction elements (such as time travel and alien interventions), whereas others do not. Examples include:

This genre tells the story of either a cataclysmic event or of what happens after a cataclysmic event. An apocalyptic story generally deals with the total or near-total destruction of civilisation or a physical world, whereas post-apocalyptic stories follow the struggles of building some form of new society. Examples include:

Biopunk centres on biotechnology, genetic engineering, and eugenics as major plot elements. These elements can be applied to humans, animals, or even food items. Examples include:

Cyberpunk depicts worlds with high levels of advanced technology contrasted against a dark picture of social decline and rampant consumerism. Cyberspace and cybernetics form a large chunk of the technological side of the genre. Examples include:

Dieselpunk shows us worlds dominated by diesel-powered machines, set anachronistically between the 1920s and 1950s. Stories are often dystopian, militaristic, and adopt a less-than-optomistic view of the present and future. Examples include:

This is an older subgenre of science fiction that relies on factual scientific and technological principles to drive the story. Any of the so-called “hard” sciences can feature as major plot elements in these stories. Examples include:

These works use comedic elements as part of the plot, or weave in humorous dialogue/prose to keep the reader/viewer entertained. Stories can be nonsensical, satirical, spoofs of more serious works, or dark comedies. Example include:

These are works that depict warfare, or which include major characters and plot settings involving the military. They can be a no-holds-barred action adventure, military thrillers with speculative elements, or a deeper work that investigates the morality of war. Examples include:

As much a subgenre as an ideology, mundane science fiction supports a more “realistic” view of science fiction. Slow interstellar travel (if any), colonisation within the Solar System, lack of extraterrestrials, and believable technology are recurring elements. While not explicitly referred to as mundane science fiction, Kim Stanley Robinson’s Mars Trilogy mostly exemplifies the manifesto that the subgenre promotes.

This genre focuses on stories in the present to a few decades in the future, almost always on Earth. It is similar to mundane science fiction in that technology is not too far advanced from what we are familiar with now, and there is a certain level of familiarity with the setting and plot elements. Speed of Dark by Elizabeth Moon is a near-future novel.

This is a genre which blends elements of science fiction with elements of fantasy. Examples include:

  • Star Wars Universe, created by George Lucas
  • Barsoom Series, by Edgar Rice Burroughs

Soft science fiction is heavily character-driven, focusing on the psychosocial effects of events and settings. They generally use the “soft” sciences as plot elements. Examples include:

Space opera is a wide-ranging subgenre encompassing a big story (usually several books/movies long), told on a grand scale, involving many characters and locations, and driven by an epic setting, usually a galactic war. Examples include:

Mixing the era of steam power with elements of speculative steam-based technologies and anachronistic gadgets is the realm of steampunk. Examples include:

Simply put, time travel stories allow the characters to travel forward or backward in time. The complications of time travel and disrupting the passage of established histories feature prominently in these works. Examples include:

Themes

Extraterrestrials invade Earth, the territory of the Solar System, or another human-occupied star system elsewhere. Alien invasions are sometimes accompanied by the theme of first contact, which explores the first overt interaction with aliens and humankind. However, first contact need not involve any military action. The contact could be initiated by either party, and it could be either an aggressive or mutually beneficial meeting. Examples include:

This theme concerns the intelligence of machines and the bearing that has on humanity. Some stories deal with artificial intelligence (AI) reaching parity or even surpassing that of humans, with either benevolent or dangerous effects. This is related to a technological singularity, whereby technology develops so fast and so uncontrollably that it changes human civilisation in unexpected ways. Examples of books dealing with artificial intelligence include:

Characteristics of this theme include (but are not limited to) political and social repression, moral and economic decline, and a large, often purposeful divide between social classes. Examples include:

Empires and other large-scale political entities have existed in science fiction for many decades. They are usually depicted as large, powerful, oppressive regimes, and are most often engaged in a military operation. Other stories show the decline of an empire through rebellion, or internal problems like corruption, espionage, and leadership challenges. Examples include:

This theme explores the development of extraterrestrial races and animals by a more advanced civilisation. It could be that an alien race gave humankind spacefaring technology, or it could delve into a primitive alien society being taught the ins-and-outs of advanced living. Sometimes, there are rules against interfering with the natural advancement of other races. Other times, it is encouraged. Examples include:

Describes an ideal world, perfect in every respect, without wars or scarcity or anything else unpleasant. Note, however, that there may be only partial utopian themes, or the gradual loss of utopia over the course of the story. Some stories depict a utopia according to a specific socio-political ideology. Examples include:

This theme comes from the Greek words xenos (stranger) and phobos (fear) and describes a fear or hatred of extraterrestrials or their culture. Stories might depict aggressive crusades against alien races or even segregation in a joint human-alien society. Examples include: