Arthur William “Big Boy” Crudup (August 24, 1905 – March 28, 1974) was an American Delta blues singer, songwriter and guitarist. He is best known, outside blues circles, for his songs “That’s All Right” (1946), “My Baby Left Me” and “So Glad You’re Mine”, later recorded by Elvis Presleyand other artists.

Crudup was born in Union Grove, Forest, Mississippi, to a family of migrant workers traveling through the South and Midwest. The family returned to Mississippi in 1926, where he sang gospel music. He had lessons with a local bluesman, whose name was Papa Harvey, and later he was able to play in dance halls and cafes around Forest. Around 1940 he went to Chicago.

He began his career as a blues singer around Clarksdale, Mississippi. As a member of the Harmonizing Four, he visited Chicago in 1939. He stayed in Chicago to work as a solo musician but barely made a living as a street singer. The record producer Lester Melrose allegedly found him while Crudup was living in a packing crate, introduced him to Hudson Whittaker, better known as Tampa Red, and signed him to a recording contract with RCA Victor‘s Bluebird label.