We have puzzled over dreams for centuries. From ancient societies, believing dreams to be messages from the gods, Freud's theory of dreams revealing our unconscious minds to modern day experiments in psychology and neuroscience, dreams continue to fascinate but also be a source of mystery. Are dreams just mental froth or do they have a purpose? This book argues that, originally, we dreamed to survive. Dreaming brains identify non-obvious associations, taking people, places, and events out of their waking-life context to uncover complex and, seemingly, unrelated connections. In our evolutionary past, survival depended on being able to detect these divergent, associative patterns to anticipate what predators and other humans might do, as we moved around to secure food and water and meet potential mates. Making associations drives many, if not all, brain functions. In the present day, dream associations may support memory, emotional stability, creativity, unconscious decision-making and prediction, while also contributing to mental illness. Written in a lively and accessible style, and showing the reader how to identify patterns in their own dreams, this book presents a highly original theory of dreaming and will be a compelling read for anyone interested in psychology, consciousness, and the arts, as well as those involved in dream research.