Lovesick Blues: The Life of Hank Williams, by Paul Hemphill (2005)
An easy read to get more deeply into Hank's story.
Hank Williams: The Biography, by Colin Escott, George Merrit, and William MacEwen (2004)
Colin Escott is a music researcher involved with creating the PBS documentary on Hank's life. The book promises to be thorough and interesting.