Here's 6 threads just from the last year with the same question
I'm not posting them to be facetious (OK, I am a bit

), but there are lots of recommendations in those threads.
http://www.blackhatworld.com/blackhat-seo/blackhat-lounge/701633-books.html
http://www.blackhatworld.com/blackhat-seo/blackhat-lounge/700017-best-business-motivational-books-read.html
http://www.blackhatworld.com/blackhat-seo/blackhat-lounge/690834-tips-inspirational-books.html
http://www.blackhatworld.com/blackhat-seo/blackhat-lounge/607226-recommend-me-any-motivational-inspirational-books-read.html
http://www.blackhatworld.com/blackhat-seo/blackhat-lounge/670074-self-improvement-become-better-you.html
http://www.blackhatworld.com/blackhat-seo/blackhat-lounge/669745-book-changed-you.html
http://www.blackhatworld.com/blackhat-seo/blackhat-lounge/610584-most-valuable-business-book-youve-read.html