Unlimited power is the first book by self help guru Tony Robbins. It’s heavy on nlp.Body Language is great. My friend tried to get me to read The Game, not my cup of tea at all. Haven't heard about Unlimited Power though.
Is it worth a read?
If you really wanna cultivate your machiavellian side, "48 Laws of Power" by Robert Greene &
"Social Engineering: The Science of Human Hacking" by Christopher Hadnagy are great tools for social manipulation when combined with Pearse.