Science fiction is a genre of fiction. It differs from fantasy in that, within the context of the story, its imaginary elements are largely possible within scientifically established or scientifically postulated laws of nature (though some elements in a story might still be pure imaginative speculation). Exploring the consequences of such differences is the traditional purpose of science fiction, making it a "literature of ideas". Science fiction is largely based on writing rationally about alternative possibilities. The settings for science fiction are often contrary to known reality.
The study of science fiction, or science fiction studies, is the critical assessment, interpretation, and discussion of science fiction literature, film, new media, fandom, and fan fiction. Science fiction scholars take science fiction as an object of study in order to better understand it and its relationship to science, technology, politics, and culture-at-large.
The field has grown considerably since the 1970s with the establishment of more journals, organizations, and conferences with ties to the science fiction scholarship community, and science fiction degree-granting programs such as those offered by the University of Liverpool and Kansas University.
The film depicts a dystopianLos Angeles in November 2019 in which genetically engineered beings called replicants—visually indistinguishable from adult humans—are manufactured by the all-powerful Tyrell Corporation. As a result of a violent replicant uprising, their use on Earth is banned, and replicants are exclusively used for dangerous or menial work on Earth's "off-world colonies". Any replicants who defy the ban and return to Earth are hunted down and "retired" by police assassins known as "blade runners". The plot focuses on a brutal and cunning group of recently escaped replicants hiding in Los Angeles and the semi-retired blade runner, Rick Deckard, who reluctantly agrees to take on one more assignment.
Blade Runner initially polarized critics: some were displeased with the pacing, while others enjoyed its thematic complexity. The film performed poorly in North American theaters. Despite the box office failure of the film, it has since become a cult classic. Blade Runner has been hailed for its production design, depicting a "retrofitted" future. It remains a leading example of the neo-noir genre. Blade Runner brought the work of author Philip K. Dick to the attention of Hollywood, and several more films have since been based on his work. Ridley Scott regards Blade Runner as "probably" his most complete and personal film. In 1993, Blade Runner was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant". In 2007, the American Film Institute named it the 97th greatest American film of all time in the 10th-anniversary edition of its 100 years ... 100 Movies list.
Seven versions of the film have been shown for various markets as a result of controversial changes made by film executives. A rushed director's cut was released in 1992 after a strong response to workprint screenings. This, in conjunction with its popularity as a video rental, made it one of the first films released on DVD, resulting in a basic disc with mediocre video and audio quality. In 2007, Warner Bros. released in select theaters, and on DVD/HD DVD/Blu-ray, the 25th anniversary digitally remastered definitive Final Cut by Scott.