Postgate wrote several mystery novels that drew on his socialist beliefs to set crime, detection and punishment in a broader social and economic context. His most famous novel is "Verdict of Twelve" (1940), his other novels include "Somebody at the Door" (1943) and "The Ledger Is Kept" (1953). (His sister and brother-in-law, the Coles, also became a successful mystery-writing duo.) After the death of H. G. Wells, Postgate edited some revisions of the two-volume "Outline of History" that Wells had first published in 1920.