"Raging Bull" (Jake Lamotta)
"Somebody up there Likes me" - Rocky Graziano

^ these two books are entertaining whether you are a boxing fan or not, both guys lived some interesting lives.

"By George" - George Foreman (real interesting, includes a ton of great stories you never hear about him)

"Flame of Pure Fire" (Jack Dempsey) is a really long but great read as well.