Timothy D. Sheehan, M.D., explores the structure and function of the human brain, emphasizing our brain's limitations and the importance of human relationships. Until about 10,000 years ago, Homo sapiens existed exclusively in tribal societies. Since then, social transformation has reshaped the world. Although the human brain remains biologically unchanged, the complexity of today's world far exceeds that of our tribal ancestors. Today, the limitations of the brain threaten human survival. Timothy D. Sheehan, M.D., explores the structure and function of the human brain in this book, answering questions such as: • How does electrical activity oscillate between the brain's functional areas? • How does our brain process sensory information and direct behavior so quickly? • Is our brain's understanding of reality oversimplifi ed and emotionally skewed? • What are the limitations of the human brain? e author also highlights how social evolution has torn away the relational fabric of tribal societies, why self-worth is increasingly based on pursuing narcissistic goals, and how a breakdown in trusted human relationships is leading more people to su er from anxiety and depression. Written in simple language, this book will help students, researchers, medical professionals, and anyone interested in how human brain function impacts our world.