There are some really good tips in here, but I've read them before (I recommend How to Win Friends and Influence People).
It mostly focuses on people at the workplace, and though it is very useful for that, I was looking for how to deal with a different breed of difficult people, so I didn't finish reading the book.
Very useful book if you apply what the book says. This book gave me some i sight into how people think, value, and feel about their work and their lives.