Subgenres of speculative fiction whose defining premise is a scientific, technological or rationally extrapolated change to the world, from a real or plausible science or a hypothetical future science. This includes movement- and era-defined subgenres such as the New Wave, cyberpunk, biopunk, dieselpunk, atompunk, nanopunk, solarpunk and hopepunk, thematic subgenres such as military, feminist, social, climate, Christian, libertarian and pastoral science fiction, and structural subgenres built on a science-fiction premise such as first contact, alien invasion, time travel, space opera, planetary romance, mecha and kaiju fiction. Alternate history is included here because the atlas's own existing genre data already classifies it as a form of science fiction. Excludes fantasy subgenres that merely borrow a science-fiction surface without a scientific premise, grouped instead under Fantasy Subgenres, and dystopian or post-apocalyptic works, grouped separately under Post-Apocalyptic and Dystopian Fiction.