First of all, I don't agree with most of the advice given in the book since this is in general a book of deception and hypocrisy. A little portion of it is devoted to tactfulness, being reticent and controlling your image which I believe are useful and permissible since they are not outright deceptions but clever manipulations.
Author's style and articulation deserves a praise. It is not a boring book.
There are some contradicting rules in it. Also, the author keeps giving examples from the same people (Napoleon, Talleyrand, Yellow Kid, Louis XIV, Michelangelo, Kissinger) again and again throughout the book. So, it feels like he has read lives of couple people to dig out several examples to fill his book.
Overall, I recommend the book but don't expect too much from it.