Norman Feather FRS FRSE PRSE (16 November 1904 – 14 August 1978), was an English nuclear physicist. Feather and Egon Bretscher were working at the Cavendish Laboratory, Cambridge in 1940, when they proposed that the 239 isotope of element 94 (plutonium) would be better able to sustain a nuclear chain reaction. This research, a breakthrough, was part of the Tube Alloys project, the secret British project during World War II to develop nuclear weapons. Feather was the author of a series of noted introductory texts on the history, fundamental concepts, and meaning of physics.