This book investigates the neurobiological mechanisms of dreaming by proposing that the dream state functions as a form of virtual reality generated by the brain. J. Allan Hobson, a prominent psychiatrist and sleep researcher, utilizes his extensive background in neurophysiology to argue that dreaming is a predictable, physiological process rather than a purely symbolic or psychological phenomenon. He presents a framework that links the activation-synthesis model of dreaming to the brain's internal simulation capabilities, providing a biological basis for the subjective experience of dreams.

Experts in the field of sleep science recognize this work as a significant contribution to the biological understanding of dreaming. Readers frequently note the technical density of the prose, which assumes a foundational knowledge of neuroanatomy and sleep physiology.