We are social animals. Our very lives depend on our relationships with people. Knowing why people do what they do is the most important tool we can possess, without which our other talents can only take us so far. Drawing from the ideas and examples of Pericles, Queen Elizabeth I, Martin Luther King Jr, and many others, Greene teaches us how to detach ourselves from our own emotions and master self-control, how to develop the empathy that leads to insight, how to look behind people's masks, and how to resist conformity to develop your singular sense of purpose.