Why does the human brain insist on interpreting the world and constructing a narrative? In this ground-breaking work, Michael S. Gazzaniga, one of the world's foremost cognitive neuroscientists, shows how our mind and brain accomplish the amazing feat of constructing our past—a process clearly fraught with errors of perception, memory, and judgment. By showing that the specific systems built into our brain do their work automatically and largely outside of our conscious awareness, Gazzaniga calls into question our everyday notions of self and reality. The implications of his ideas reach deeply into the nature of perception and memory, the profundity of human instinct, and the ways we construct who we are and how we fit into the world around us. Over the past thirty years, the mind sciences have developed a picture not only of how our brains are built but also of what they were built to do. The emerging picture is wonderfully clear and pointed, underlining William James's notion that humans have far more instincts than other animals. Every baby is born with circuits that compute information enabling it to function in the physical world. Even what helps us to establish our understanding of social relations may have grown out of perceptual laws delivered to an infant's brain. Indeed, the ability to transmit culture—an act that is only part of the human repertoire—may stem from our many automatic and unique perceptual-motor processes that give rise to mental capacities such as belief and culture. Gazzaniga explains how the mind interprets data the brain has already processed, making "us" the last to know. He shows how what "we" see is frequently an illusion and not at all what our brain is perceiving. False memories become a part of our experience; autobiography is fiction. In exploring how the brain enables the mind, Gazzaniga points us toward one of the greatest mysteries of human evolution: how we become who we are.