Science fiction, often called sci-fi or SF, is a type of speculative fiction that imagines future scientific or technological advances. Over time, common elements in science fiction have expanded. These include space exploration, alien life, time travel, and robotics. Later, themes like parallel universes, societies with harsh conditions, and changes to living things became common. Recently, topics such as information technology, ideas about human enhancement, and environmental challenges have also appeared. Science fiction often examines how people might react to these imagined scientific developments.

People have debated what exactly defines science fiction for a long time. The genre includes many subgenres. For example, hard science fiction focuses on scientific accuracy, while soft science fiction highlights social sciences. Other subgenres include space opera, which centers on adventure in a universe where space travel is common; cyberpunk, which explores how technology affects society; and climate fiction, which deals with environmental issues.

Early examples of science fiction may date back to ancient times. Some books from the Scientific Revolution and Enlightenment were considered early science-fantasy stories. The modern genre began mainly in the 19th and early 20th centuries, when writers used technological progress as inspiration. Mary Shelley’s Frankenstein, written in 1818, is often seen as the first true science fiction novel. Jules Verne and H.G. Wells were important in developing the genre. In the 20th century, the Golden Age of Science Fiction helped the genre grow, and it expanded with space operas, dystopian stories, and magazines with science fiction stories.

Science fiction has influenced not only books but also movies, TV shows, and culture overall. It can critique current society, imagine different possibilities, provide entertainment, and inspire a sense of wonder.

Definitions

The Encyclopedia of Science Fiction, edited by John Clute and Peter Nicholls in 1993, discusses the problem of defining the science fiction genre.

American writer and biochemistry professor Isaac Asimov wrote, "Science fiction can be defined as the part of literature that focuses on how people respond to changes in science and technology."

Science fiction writer Robert A. Heinlein wrote, "A simple definition of most science fiction could be: realistic ideas about possible future events, based on a strong understanding of the real world, past and present, and on a clear knowledge of the scientific method."

American science fiction author and editor Lester del Rey wrote, "Even people who love science fiction have trouble explaining what it is," and no "perfect definition" exists because "science fiction has no clear boundaries."

Another definition is provided in The Literature Book by publisher DK: "Stories that are currently impossible with today’s technology, but imagine what could happen if science advances, or stories that explore imaginative ideas based on science, such as societies on Earth or other planets that developed differently from ours."

Science fiction fans often decide for themselves what counts as science fiction. David Seed suggests it may be better to describe science fiction as the overlap of more specific types of stories. American science fiction author, editor, and critic Damon Knight said, "Science fiction is what we call it when we point to something and say, 'That’s science fiction.'"

American magazine editor, science fiction writer, and literary agent Forrest J Ackerman is credited with first using the term "sci-fi" (similar to the popular term "hi-fi") around 1954. The first known use in print was by movie critic Jesse Zunser in January 1954, who described the book Donovan’s Brain. As science fiction became more popular, writers and fans began to link the term "sci-fi" with low-quality stories and low-budget, low-tech movies. By the 1970s, critics like Damon Knight and Terry Carr used "sci-fi" to separate less serious stories from more thoughtful science fiction.

Australian literary scholar and critic Peter Nicholls wrote around 1993 that SF (or sf) is "the preferred way to shorten the term within the science fiction writing and reading community."

Robert Heinlein believed the term "science fiction" was not enough to describe all works in the genre. He suggested using the term "speculative fiction" instead for stories that are more "serious" or "thoughtful."

Literature

Some experts believe that science fiction began in ancient times, when people often mixed stories about the impossible with real events. A book called A True Story, written by Lucian in the 2nd century CE, includes ideas that are now common in science fiction, such as traveling to other planets, meeting alien beings, fighting battles in space, and creating life artificially. Some people think this is the first science fiction novel. Other works, like stories from The Arabian Nights, The Tale of the Bamboo Cutter, and Theologus Autodidactus, are also said to have early science fiction elements.

Books written during the Scientific Revolution and the Age of Enlightenment are considered early examples of science fiction. These include New Atlantis by Francis Bacon (1627), Somnium by Johannes Kepler (1634), The Blazing World by Margaret Cavendish (1666), Gulliver's Travels by Jonathan Swift (1726), and Micromégas by Voltaire (1752).

Isaac Asimov and Carl Sagan believed that Somnium by Johannes Kepler was the first science fiction story. It describes a journey to the Moon and how the Earth moves as seen from there. Kepler is sometimes called the "father of science fiction."

After the 17th century, when novels became a popular form of writing, Mary Shelley’s Frankenstein (1818) and The Last Man (1826) helped shape the science fiction novel. Some critics say Frankenstein was the first science fiction book. Edgar Allan Poe wrote stories like The Unparalleled Adventure of One Hans Pfaall (1835), which is about a trip to the Moon.

Jules Verne was known for his careful descriptions of science, especially in Twenty Thousand Leagues Under the Seas (1870). In 1887, a book called El anacronópete by Enrique Gaspar y Rimbau introduced the idea of a time machine. A French/Belgian writer named J.-H. Rosny aîné (1856–1940) used the word "astronaut" for the first time in his novel The Navigators of Infinity (1925).

Many critics think H. G. Wells was one of the most important science fiction writers, or even "the Shakespeare of science fiction." His books, such as The Time Machine (1895), The Invisible Man (1897), and The War of the Worlds (1898), explored ideas like alien invasions, invisibility, and time travel. In his non-fiction works, he predicted things like airplanes, tanks, space travel, and the internet.

Edgar Rice Burroughs’ A Princess of Mars (1912) was the first in a series of stories about a fictional planet called Barsoom. The hero of these stories is John Carter.

A book called We (1924), written by Yevgeny Zamyatin, is one of the first dystopian novels. It describes a world ruled by a strict, unified government.

In 1926, Hugo Gernsback started the first American science fiction magazine, Amazing Stories. In its first issue, he said:

In 1928, E. E. "Doc" Smith’s novel The Skylark of Space (co-written with Lee Hawkins Garby) appeared in Amazing Stories. It is often called the first great space opera. That same year, Philip Francis Nowlan’s story Armageddon 2419 about Buck Rogers was also published in Amazing Stories. This story later inspired a science fiction comic strip.

Last and First Men: A Story of the Near and Far Future (1930), written by Olaf Stapledon, is a science fiction novel that describes the future of humanity over two billion years.

In 1937, John W. Campbell became the editor of Astounding Science Fiction magazine. This event is sometimes called the start of the Golden Age of Science Fiction, a time when stories celebrated scientific progress. This period is often said to have ended in 1946, but some include the late 1940s and 1950s.

In 1942, Isaac Asimov began writing the Foundation series, which tells the story of the rise and fall of galactic empires. The series also introduced the idea of psychohistory. It later won a Hugo Award for "Best All-Time Series."

Theodore Sturgeon’s More Than Human (1953) explored how humans might evolve in the future. In 1957, Ivan Yefremov’s Andromeda: A Space-Age Tale described a future communist society in space. It is considered one of the most important Soviet science fiction books.

In 1959, Robert A. Heinlein’s Starship Troopers was different from his earlier stories. It is one of the first and most influential examples of military science fiction. It also introduced the idea of powered armor exoskeletons. A German science fiction series called Perry Rhodan, which began in 1961, became one of the most popular science fiction books ever written.

During the 1960s and 1970s, a style of science fiction called "New Wave" focused on creative writing and complex ideas.

In 1961, Stanisław Lem’s Solaris was published in Poland. It explored the limits of human understanding as characters tried to study an ocean on a distant planet. Lem’s work inspired ideas about nanotechnology, virtual reality, and artificial intelligence.

In 1965, Frank Herbert’s Dune imagined a detailed future society. In 1967, Anne McCaffrey started a science fiction series called Dragonriders of Pern. Two stories in her first book, Dragonflight, helped her win the first Hugo or Nebula Award given to a female author.

In 1968, Philip K. Dick’s Do Androids Dream of Electric Sheep? became the basis for the Blade Runner movie. In 1969, Ursula K. Le Guin’s The Left Hand of Darkness described a planet where people have no fixed gender. It is one of the most important examples of science fiction that explores social and feminist themes.

In 1979, Science Fiction World magazine began publishing in China. It became the most popular science fiction magazine in the world, with a large readership.

In 1984, William Gibson’s Neuromancer helped popularize the cyberpunk genre and the term "cyberspace." That same year, Octavia Butler’s short story Speech Sounds won a Hugo Award for Best Short Story.

Film

One of the first science fiction films ever made was A Trip to the Moon from 1902. This film was directed by a French filmmaker named Georges Méliès. It inspired future filmmakers by showing new ways to use creativity and fantasy. Méliès used special effects and editing techniques that became important parts of filmmaking and were copied by others.

The 1927 film Metropolis was directed by Fritz Lang. It was the first full-length science fiction film. Although it was not well received when it was released, it is now considered one of the greatest films ever made.

In 1954, the film Godzilla, directed by Ishirō Honda, began a subgenre of science fiction called kaiju. This type of film features large creatures, often attacking cities or fighting other monsters.

The 1968 film 2001: A Space Odyssey was directed by Stanley Kubrick and based on stories by Arthur C. Clarke. This film improved on earlier science fiction movies by offering a larger scale and higher quality. It also influenced many later science fiction films.

The original Planet of the Apes movie, released in 1968, was directed by Franklin J. Schaffner. It was based on the 1963 French novel La Planète des Singes by Pierre Boulle. The film shows a world after a disaster where intelligent apes control humans. It was praised by both audiences and critics.

In 1977, George Lucas started the Star Wars series with the film of the same name. This series, often called a space opera, became a major part of global popular culture. It is now the third-highest-grossing film series in history.

Since the 1980s, science fiction films, along with fantasy, horror, and superhero films, have been the most common types of big-budget movies in Hollywood. Science fiction films often mix with other genres. Examples include film noir (Blade Runner, 1982), family (E.T. the Extra-Terrestrial, 1982), war (Enemy Mine, 1985; Starship Troopers, 1997), comedy (Spaceballs, 1987; Galaxy Quest, 1999), animation (WALL-E, 2008; Big Hero 6, 2014), Western (Serenity, 2005), action (Edge of Tomorrow, 2014; The Matrix, 1999), adventure (Jupiter Ascending, 2015; Interstellar, 2014), mystery (Minority Report, 2002), thriller (Ex Machina, 2014), drama (Melancholia, 2011; Predestination, 2014), and romance (Eternal Sunshine of the Spotless Mind, 2004; Her, 2013).

Television

Science fiction and television have always been closely connected. Before television became common in the late 1940s and early 1950s, stories about television and similar technology often appeared in science fiction books and plays.

The first science fiction television program was a 35-minute version of the play RUR, written by Czech author Karel Čapek. It was broadcast live from the BBC's Alexandra Palace studios on February 11, 1938. The first popular science fiction program on American television was Captain Video and His Video Rangers, a children’s adventure show that aired from June 1949 to April 1955.

The original The Twilight Zone series, created and narrated by Rod Serling, ran from 1959 to 1964. Serling also wrote or co-wrote most of the episodes. The show included fantasy, suspense, horror, and science fiction, with each episode telling a complete story. Critics have called it one of the best TV programs of any genre.

The animated series The Jetsons, which was a comedy, aired for one season (1962–1963). It predicted many inventions now used daily, such as flat-screen televisions, computer-like screens for newspapers, video chat, and home treadmills.

In 1963, the series Doctor Who premiered on BBC Television. It had a time-travel theme and ran until 1989. It was revived in 2005 and has been popular worldwide, influencing many science fiction shows.

Other British science fiction dramas from the 1970s include UFO (1970–1971), The Tomorrow People (1973–1979), Space: 1999 (1975–1977), and Blake's 7 (1978–1981). Notable programs from the 1960s include The Outer Limits (1963–1965), Lost in Space (1965–1968), and The Prisoner (1967–1968).

The original Star Trek series, created by Gene Roddenberry, premiered in 1966 on NBC. It combined space opera and space Western styles. Though not very popular at first, it gained fans through syndication and became a major franchise with many films, shows, and books. Later Star Trek series include The Next Generation (1987–1994), Deep Space Nine (1993–1999), Voyager (1995–2001), Enterprise (2001–2005), Discovery (2017–2024), Picard (2020–2023), and Strange New Worlds (2022–present).

The miniseries V premiered in 1983 on NBC. It told the story of aliens trying to take over Earth. Red Dwarf, a comedy science fiction show, aired on BBC Two from 1988 to 1999 and later on Dave. The X-Files, which focused on UFOs and conspiracy theories, was created by Chris Carter and aired on Fox from 1993 to 2002, and again from 2016 to 2018.

The film Stargate, about ancient astronauts and teleportation, was released in 1994. The series Stargate SG-1 began in 1997 and ran for 10 seasons (1997–2007). Other shows based on Stargate include Stargate Infinity (2002–2003), Stargate Atlantis (2004–2009), and Stargate Universe (2009–2011).

Other 1990s series include Quantum Leap (1989–1993) and Babylon 5 (1994–1999). The Syfy channel, originally called The Sci-Fi Channel when it started in 1992, focuses on science fiction, supernatural horror, and fantasy.

The space-Western series Firefly premiered in 2002 on Fox. It is set in the year 2517, after humans colonize a new star system, and follows the adventures of a crew on a spaceship called Serenity. The series Orphan Black ran for five seasons starting in 2013. It follows a woman who takes on the identity of one of her genetically identical clones. In late 2015, Syfy aired The Expanse, a critically praised American show about humanity’s colonization of the Solar System. Later seasons of The Expanse were shown on Amazon Prime Video.

Social influence

Science fiction became more popular during the first half of the 20th century because people respected science and because new technologies were being developed quickly. Science fiction often predicts future scientific and technological advances. Some stories, like those by Arthur C. Clarke and Star Trek, show how these advances might improve life and society. Other stories, such as H.G. Wells’s The Time Machine and Aldous Huxley’s Brave New World, warn about possible negative effects of these changes.

In 2001, the National Science Foundation studied how people who read science fiction think about science compared to others. The study found that these readers often support space exploration and efforts to communicate with life beyond Earth. Carl Sagan said that many scientists who work in space exploration were first interested in science because of science fiction.

Science fiction has predicted real inventions, such as the atomic bomb, robots, and borazon. In the 2020 TV show Away, astronauts use a Mars rover called InSight to listen for a landing on Mars. In 2022, scientists used InSight to listen for a spacecraft landing on Mars.

Science fiction helps people examine how societies interact with others and imagine future relationships. It also represents differences in identity. Brian Aldiss called science fiction "cultural wallpaper," meaning it is a common part of culture.

Science fiction is used by writers to share ideas and by teachers in many subjects. George Edgar Slusser said science fiction is a global literary form that has expanded into movies, games, and other new media. He noted that combining science and humanities is important for the future.

Science fiction has sometimes been used to protest social issues. George Orwell’s Nineteen Eighty-Four is a famous example of a story that criticizes authoritarian governments. James Cameron’s film Avatar protested against imperialism, like the colonization of the Americas. In Latin America and Spain, science fiction often explores themes of authoritarianism.

Themes like robots, artificial humans, human clones, and intelligent computers have been major parts of science fiction since Mary Shelley’s Frankenstein. Some critics believe these themes show concerns about loneliness and alienation in modern society.

Feminist science fiction asks questions about how society defines gender roles, how reproduction affects gender, and how power is shared between genders. Some stories show worlds without gender differences or with worsened gender inequalities, showing the need for continued feminist efforts.

Climate fiction, or cli-fi, focuses on climate change and global warming. Courses in literature and environmental studies may include cli-fi in their lessons. These topics are also discussed in other media outside of science fiction.

Libertarian science fiction focuses on ideas from right-wing libertarianism, such as individual freedom and private property. Robert A. Heinlein, a popular author in this style, wrote books like The Moon is a Harsh Mistress and Stranger in a Strange Land.

Science fiction comedy often makes fun of society and the traditions of more serious science fiction stories.

Science fiction is said to inspire a sense of wonder. David Hartwell, a science fiction editor, said science fiction combines the logical and the amazing, creating a feeling of awe.

Carl Sagan wrote about how science fiction influenced his interest in science.

In 1967, Isaac Asimov talked about changes happening in the science fiction community.

Study

The field of science fiction studies involves the careful analysis, explanation, and discussion of science fiction books, movies, TV shows, digital media, fan communities, and fan-created stories. Experts in this field study science fiction to learn more about it and how it connects to science, technology, politics, other types of stories, and culture overall.

Science fiction studies began around the start of the 20th century, but it became a formal area of study later. This happened with the creation of academic journals like Extrapolation (1959), Foundation: The International Review of Science Fiction (1972), and Science Fiction Studies (1973). In 1970, the first organizations dedicated to studying science fiction were formed: the Science Fiction Research Association and the Science Fiction Foundation. Since the 1970s, the field has grown with more journals, groups, conferences, and university programs that offer degrees in science fiction, such as those at the University of Liverpool.

Science fiction has traditionally been divided into two types: hard and soft. This division depends on how realistic the science in the story is. However, this distinction has been questioned more in the 21st century. Some authors, like Tade Thompson and Jeff VanderMeer, note that stories focusing on physics, astronomy, math, and engineering are often called hard science fiction. Stories focusing on biology, social sciences, and other fields are usually called soft science fiction, even if the science in those stories is not always precise.

Max Gladstone described hard science fiction as stories where the math is correct, but he noted that this definition can make some stories seem outdated as scientific ideas change. Michael Swanwick rejected the traditional definition of hard science fiction, saying it is instead about characters working to solve problems with effort, patience, and the understanding that the universe may not support them.

Ursula K. Le Guin criticized the traditional divide between hard and soft science fiction, explaining that hard science fiction writers often focus only on physics, astronomy, and chemistry, while ignoring biology, sociology, and anthropology. She emphasized her interest in human behavior and the social sciences.

Some critics still question whether science fiction and other genre stories have literary value. However, some well-known authors have written works that others classify as science fiction. Mary Shelley, for example, wrote Frankenstein; or, The Modern Prometheus (1818), which is part of the Gothic tradition. Kurt Vonnegut, a respected author, is also known for works that include science fiction themes.

Other science fiction writers whose works are widely regarded as serious literature include Ray Bradbury (Fahrenheit 451, The Martian Chronicles), Arthur C. Clarke (Childhood's End), and Paul Myron Anthony Linebarger (writing under the name Cordwainer Smith). Doris Lessing, who later won the Nobel Prize in Literature, wrote a series of science fiction novels titled Canopus in Argos: Archives (1979–1983), which explore themes of advanced civilizations influencing humans.

David Barnett noted that some books use common science fiction ideas but are not labeled as science fiction by their authors or publishers. These include The Road (2006) by Cormac McCarthy, Cloud Atlas (2004) by David Mitchell, The Gone-Away World (2008) by Nick Harkaway, The Stone Gods (2007) by Jeanette Winterson, and Oryx and Crake (2003) by Margaret Atwood. Atwood argued that works like The Handmaid's Tale should not be called science fiction but instead fall under the category of speculative fiction. She criticized science fiction as "talking squids in outer space."

In his book The Western Canon, literary critic Harold Bloom included Brave New World, Stanisław Lem's Solaris, Kurt Vonnegut's Cat's Cradle, and The Left Hand of Darkness as important works of Western literature, even though Lem refused to identify his work as science fiction.

In her 1976 essay "Science Fiction and Mrs Brown," Ursula K. Le Guin was asked, "Can a science fiction writer write a novel?" She responded that all novels focus on characters and that great novelists use characters to share their messages, unlike poets, historians, or writers of pamphlets.

Orson Scott Card is best known for his 1985 novel Ender's Game. He believes that science fiction stories contain their own messages and ideas, so they do not need traditional literary techniques that he calls gimmicks or games.

In 1998, Jonathan Lethem wrote an essay titled "Close Encounters: The Squandered Promise of Science Fiction" for The Village Voice. In it, he recalled how Thomas Pynchon's Gravity's Rainbow was nominated for the Nebula Award in 1973 but lost to Arthur C. Clarke's Rendezvous with Rama. Lethem suggested this event marked the end of hopes that science fiction would join mainstream literature. That same year, science fiction author and physicist Gregory Benford stated that science fiction might be the most important genre of the 20th century, even though it is not yet fully accepted by traditional literary circles.

Community

Science fiction has been written by authors from many different cultures and places. According to statistics from 2013, 78% of books published by Tor Books were written by men, and 22% were written by women. A discussion about voting groups for the 2015 Hugo Awards showed a disagreement in the science fiction community. Some people wanted more diverse stories and authors to be honored, while others preferred stories that followed more traditional science fiction styles.

Some of the most important awards in science fiction include the Hugo Award, given by the World Science Fiction Society at Worldcon and voted on by fans; the Nebula Award, given by the Science Fiction and Fantasy Writers of America and voted on by authors; the John W. Campbell Memorial Award, chosen by a group of writers; and the Theodore Sturgeon Memorial Award, chosen by a group for short stories. A well-known award for science fiction movies and TV shows is the Saturn Award, given each year by The Academy of Science Fiction, Fantasy, and Horror Films.

Other awards include Canada’s Prix Aurora Awards, the Endeavour Award for works from the U.S. Pacific Northwest, and awards for specific interests, such as the Chesley Award for art or the World Fantasy Award for fantasy. Magazines sometimes hold polls, like the Locus Award.

Science fiction conventions, often called "cons" (such as Comic-con), are held in cities worldwide. These events serve local, regional, national, or international groups. Some conventions cover all areas of science fiction, while others focus on specific interests like media or music. Most conventions are organized by volunteers in non-profit groups, though events focused on media are often run by businesses.

Science fiction fandom began with letters in the magazine Amazing Stories. Fans started writing to each other and sharing their ideas in informal publications called fanzines. Later, they formed local clubs and held the first science fiction conventions in the 1930s.

The first online science fiction community was the SF Lovers Community, which began as a mailing list in the late 1970s. In the 1980s, online groups called Usenet expanded the reach of fans. In the 1990s, the internet helped science fiction fans connect through websites.

The first science fiction fanzine, The Comet, was published in 1930 by the Science Correspondence Club in Chicago, Illinois. As of 2025, Ansible, edited by David Langford, is one of the most well-known fanzines. Other fanzines that have won Hugo Awards include File 770, Mimosa, and Plokta. Artists who worked on fanzines, such as Brad W. Foster, Teddy Harvia, and Joe Mayhew, have become famous in the field. The Hugo Awards include a category for Best Fan Artists.

Elements

Science fiction often includes these elements:

• Time settings in the future or different versions of history;
• Imagined or future technology such as brain-computer connections, genetic changes, advanced computers, robots, futuristic weapons, and ray guns;
• Space travel or settings in outer space, on other planets, underground Earth, or in other universes;
• Fictional biology ideas such as aliens, people with unusual traits, and humans with special abilities;
• Unproven scientific ideas such as teleportation, time travel, or moving faster than light;
• New or different social or political systems, such as perfect societies, harsh worlds, post-disaster settings, or worlds with no scarcity;
• Stories about how humans might change in the future on Earth or other planets;
• Unusual abilities such as controlling minds, reading thoughts, or moving objects with the mind.

Religious fanaticism is closely connected to science fiction. It uses rituals and extreme beliefs to explain or misunderstand the world. Science fiction stories often explore cultural norms, trends, and social changes. Religion and religious fanaticism also critique the world in similar ways. In these stories, the main character usually faces challenges from extreme actions by fanatics, but the hero often works to stop them.

Subgenres

Science fiction is a type of fiction. Within science fiction, there are smaller groups called subgenres. These subgenres can be divided in many different ways. A book titled Critical Terms for Science Fiction and Fantasy by scientist Gary K. Wolfe lists more than 30 types of science fiction. This list does not include science fantasy, which is a mix of science fiction and fantasy.