In the book, Mao comes across as a psychopathic schemer who will do anything to anyone to get where he needs to go. This includes killing anyone or anything in his way.
It's a good book but I would point out two things. Firstly it gets really depressing after a while when you read how he moves from one violent act to another. Secondly, if you read most biographies you get an extensive list if references in the back. That wasn't as present in this book, so is something you might want to bear in mind when you read this book.
Also, there was one thing I couldn't understand (and the book doesn't explain to well). I couldn't understand why the other more sensible communists didn't act against his when they had the chance, but that's only a minor grumble.