Douglas Adams was the much-loved author of the Hitchhiker's Guides, all of which have sold more than 15 million copies worldwide.

Adams is best known as the author of The Hitchhiker's Guide to the Galaxy, which originated in 1978 as a BBC radio comedy before developing into a "trilogy" of five books that sold more than 15 million copies in his lifetime and generated a television series, several stage plays, comics, a computer game, and in 2005 a feature film. Adams's contribution to UK radio is commemorated in The Radio Academy's Hall of Fame.

Adams also wrote Dirk Gently's Holistic Detective Agency (1987) and The Long Dark Tea-Time of the Soul (1988), and co-wrote The Meaning of Liff (1983), The Deeper Meaning of Liff (1990), Last Chance to See (1990), and three stories for the television series Doctor Who. A posthumous collection of his work, including an unfinished novel, was published as The Salmon of Doubt in 2002.

Adams became known as an advocate for environmentalism and conservation, and also as a lover of fast cars, cameras, technological innovation, and the Apple Macintosh. He was a staunch atheist, imagining a sentient puddle who wakes up one morning and thinks, "This is an interesting world I find myself in—an interesting hole I find myself in—fits me rather neatly, doesn't it? In fact it fits me staggeringly well, must have been made to have me in it!" to demonstrate his view that the fine-tuned Universe argument for God was a fallacy. Biologist Richard Dawkins dedicated his book The God Delusion (2006) to Adams, writing on his death that "Science has lost a friend, literature has lost a luminary, the mountain gorilla and the black rhino have lost a gallant defender."