Atomsk, first published in 1949, is a Cold War spy novel by "Carmichael Smith", one of several pseudonyms used by American writer Paul Linebarger, who wrote fiction most prolifically as Cordwainer Smith.

Drawing on Linebarger's own expertise in the field of psychological warfare, the book is a study of the personality of a U.S. operative (Major Michael Dugan) who has little in common with James Bond except his extreme resourcefulness under cover and in danger.

A man of many identities who sees himself to some extent as a blank sheet, he goes from calling himself "Comrade Nobody" to saying "I'm anybody".

Written two years after Winston Churchill's Sinews of Peace address, Atomsk is the first espionage novel of the Cold War, inaugurating a genre exemplified by writers such as Ian Fleming and John Le Carré.

Paper copies regularly command figures in the hundreds of U.S. dollars in the second-hand market, even though it is also available as an inexpensive e-book.