(ald) (1912-1991) US film director. He specialized in thrillers, Westerns, and police dramas. Two of his low-budget features, the prison film Riot in Cell Block 11 1954 and the science-fiction story Invasion of the Body Snatchers 1956, are widely recognized for transcending their lack of resources. Siegel moved on to bigger budgets, but retained his taut, acerbic view of life in such films as the Clint Eastwood vehicles Coogan’s Bluff 1969, The Beguiled, and Dirty Harry both 1971.