The Hitchhiker's Guide to the Galaxy is a comic science fiction series created by Douglas Adams that has become popular among fans of the genre and members of the scientific community. Phrases from it are widely recognised and often used in reference to, but outside the context of, the source material. Many writers on popular science, such as Fred Alan Wolf, Paul Davies, and Michio Kaku, have used quotations in their books to illustrate facts about cosmology or philosophy.

"42" is the seventh episode of the third series of British science fiction television series Doctor Who. It was first broadcast on BBC One on 19 May 2007. It was the first episode written by Chris Chibnall, the showrunner and lead writer of Doctor Who from the 11th series to the 2022 specials.