Keb' Mo', Monday, July 25, at the Fox Theatre, with Koko Taylor, got his start as a multitalented L.A. session player and sideman to Papa John Creach and Monk Higgins. His first album, Rainmaker, appeared in 1980 on Chocolate City, a defunct division of Casablanca Records, under his given name, Kevin Moore. But it wasn't until Moore (christened Keb' Mo' by his peers) began playing the blues in a style influenced by Son House and Muddy Waters did he develop his true musical identity. The guitarist's self-titled debut on OKeh Records is so impressive that the producers of the upcoming Robert Johnson docudrama Can't You Hear the Wind Howl? chose Mo' to portray the legendary bluesman. It's a perfect fit.