A new popular science book exploring the cutting edge science explaining human altruism and psychopathy, how closely they can be mapped, and how the potential to be more compassionate and kind exists in all of us. A fine example of a book that looks deeper, showing how an ancient part of the brain--central to our emotional lives--plays a pivotal role in who we are and what we do. It's a sharp analysis sprinkled with relatable examples, and an excellent brain book