Freeman Wills Crofts (June 1, 1879 Dublin - April 11, 1957 Worthing) was an Irish-British mystery author, one of the 'Big Four' of the Golden Age of Detective Fiction.
He attended Methodist College and Campbell College in Belfast. At the age of eighteen, he was employed as a pupil on the civil engineering staff of the Belfast Counties Railway. He held various positions in railway engineering, becoming Chief Assistant Engineer at the Railway, then known as the L.M.S. Northern Counties Committee. While there, Crofts wrote his first novel, The Cask (1920), which established him as a new master of detective fiction. Thereafter he wrote several fine mysteries about his favorite detective, Inspector Joseph French, including Inspector French's Greatest Case (1924). He also wrote one religious book, The Four Gospels in One Story, several short stories, and short plays for the BBC.
In 1912 he wed Mary Canning, the daughter of J.J. Canning of Coleraine, Northern Ireland. In 1939 he was elected a fellow of the Royal Society of Arts.