I loved Walt Disney: The Triumph of the American Imagination by
Neal Gabler. The early sections of the book - like when they were making Snow White were so compelling I couldn't put it down. It's not only a biography - it's also a history of animated film-making in many ways. Excellent!
Walt Disney: An American Original by Bob Thomas
I'll repeat the Neal Gabler suggestion; wonderful book.
Slightly related, I'd also recommend The Hand Behind the Mouse by John Kenworthy. It's a biography about Ub Iwerks and large portions of the book are dedicated to his time with Walt Disney Studios and his relationship with Walt. It's a great read.
I have not read one and was wondering what the Walt fans would recommend.
Thanks.