What is a dream? Why do we dream? How do our bodies and minds use dreams? These questions are the starting point for this unprecedented, astonishing study of the role and significance of dreams, from the beginning of human history. It is an investigation on the grand scale, encompassing literature, anthropology, religion, and science, one that articulates the essential place dreams occupy in human culture, and how they functioned as the catalyst that compelled us to transform our earthly habitat into a human world. Ribeiro explores the advances that contemporary neuroscience, biochemistry and psychology have made into the connections between sleep, dreams, and learning. He explains what dreams have taught us about the neural basis of memory and the transformation of memory in recall.