Frankenstein, The Time Machine, Star Trek, Dune, 1984, Blade Runner—science fiction has been explained as a combination of romance, science, and prophecy; as a genre based on an imagined alternative to the reader's environment; and as a form of fantastic fiction and historical literature. It has also been argued that science fiction narratives are the most engaged, socially relevant, and responsive to the modern technological environment. In this Very Short Introduction, David Seed doesn't offer a history of science fiction, but instead attempts to tie examples of science fiction to different historical moments, in order to demonstrate how science fiction has evolved over time, especially the emergence of science fiction as a popular genre in the twentieth century. Seed looks not only at literature, but also at drama and poetry, as well as film. Examining recurrent themes in science fiction, he looks at voyages into space, the concept of the alien and alternative social identities, the role of technology in science fiction, and its relation to time—in the past, present, and future.