Steampunk is a subgenre of science fiction and/or fantasy that incorporates technology and aesthetic designs inspired by 19th-century industrial steam-powered machinery. Steampunk works are often set in an alternate history of the 19th century's British Victorian era or the American "Wild West", in a post-apocalyptic future during which steam power has maintained mainstream usage, or in a fantasy world that similarly employs steam power. Steampunk may, therefore, be described as neo-Victorian. Steampunk perhaps most recognisably features anachronistic technologies or retro-futuristic inventions as people in the 19th century might have envisioned them, and is likewise rooted in the era's perspective on fashion, culture, architectural style, and art. Such technology may include fictional machines like those found in the works of H.G. Wells and Jules Verne, or the modern authors Philip Pullman, Scott Westerfeld, Stephen Hunt, and China Miéville. Other examples of steampunk contain alternative history-style presentations of such technology as lighter-than-air airships, analogue computers, or such digital mechanical computers as Charles Babbage's Analytical Engine.

The first known written use of the term steampunk was in 1987, though it now retroactively refers to many works of fiction created even as far back as the 1950s or 1960s. Michael Moorcock's series "The Warlord of the Air", written in the 1970s, is considered among the definitive works of steampunk literature.

Harry Turtledove has occasionally dabbled in the steampunk genre.

The novel The Two Georges, written by Richard Dreyfuss and Turtledove, is a quintessential steampunk novel, set in a world characterised by many of the genre's established hallmarks: steam-powered automobiles, general use of airships for passenger transportation, and a survival of the British Empire at the close of the 20th century.

Turtledove's The Guns of the South, which uses time-travel to introduce the AK-47 and other late-20th-century accessories into the American Civil War, creates a world which can, with some reservations, be considered steampunk as well.

On the Train, comprising Turtledove's "All Aboard!" and his daughter Rachel's "First Passage", revolves around a railroad which is powered by both science and magic.