The Art of War
This book, like anything Chinese and more than a thousand years old, is dense and hard to read. The only way to extract any value from it (unless you're just into the poetry of the translation) is by thinking really hard about what's said. <br/><br/>And I'm sure there are some that think they already figured out all of Sun Tzu's wisdom already, but believe me: it's not common sense if the majority don't know it. QED.