Learn to measure the people you deal with by the depth of their soul, and if possible associate as much as you can with those of the expansive variet… - Robert Greene

People are rarely who they seem to be. Lurking beneath their polite, affable exterior is inevitably a dark, shadow side consisting of the insecurities and the aggressive, selfish impulses they repress and carefully conceal from public view. This dark side leaks out in behavior that will baffle and harm you. Learn to recognize the signs of the Shadow before they become toxic. See people’s overt traits—toughness, saintliness, et cetera—as covering up the opposite quality. You must become aware of your own dark side. In being conscious of it you can control and channel the creative energies that lurk in your unconscious. By integrating the dark side into your personality, you will be a more complete human and will radiate an authenticity that will draw people to you.

Everything in life can be taken away from you and generally will be at some point. Your wealth vanishes, the latest gadgetry suddenly becomes passé, your allies desert you. But if your mind is armed with the art of war, there is no power that can take that away. In the middle of a crisis, your mind will find its way to the right solution. Having superior strategies at your fingertips will give your maneuvers irresistible force. As Sun-tzu says, “Being unconquerable lies with yourself.

Learn to destroy your enemies by opening holes in their own reputations. Then stand aside and let public opinion hang them.