David Williams was a writer best known for his crime-novel series featuring the banker Mark Treasure and police inspector DI Parry.

After serving as Naval Officer in the Second World War, Williams completed a History degree at St Johns College, Oxford before embarking on a career in advertising. He became a full-time fiction writer in 1978. Williams wrote twenty-three novels, seventeen of which were part of the Mark Treasure series of whodunnits which began with Unholy Writ (1976). His experience in both the Anglican Church and the advertising world informed and inspired his work throughout his career.

Two of Williams' books were shortlisted for the Crime Writers' Association Gold Dagger Award, and in 1988 he was elected to the Detection Club.