Scott Freeman, Otis!: The Otis Redding Story (2001)
There's a fair amount of Georgia pride in this biography—Freeman's previous work includes a book on the Allman Brothers. This is a highly readable account of Redding's life and the evolution of the Memphis Sound that Redding helped create.
Peter Guralnick, Sweet Soul Music: Rhythm and Blues and the Southern Dream of Freedom (1999)
Otis Redding joins a host of soul artists such as James Brown, Sam Cooke, Aretha Franklin, James Carr, Solomon Burke, Al Green, and Wilson Pickett in Guralnick's interesting and authoritative analysis of soul music's evolution from the 1950s forward.