Book excerpt: In this book J. Allan Hobson sets out a compelling—and controversial—theory of consciousness. Our brain-mind, as he calls it, is not a fixed identity but a dynamic balancing act between the chemical systems that regulate waking and dreaming. With a new foreword by the author. In this book, J. Allan Hobson sets out a compelling—and controversial—theory of consciousness. Our brain-mind, as he calls it, is not a fixed identity but a dynamic balancing act between the chemical systems that regulate waking and dreaming. Drawing on his work both as a sleep researcher and as a psychiatrist, Hobson looks in particular at the strikingly similar chemical characteristics of the states of dreaming and psychosis. His underlying theme is that the form of our thoughts, emotions, dreams, and memories derive from specific nerve cells and electrochemical impulses described by neuroscientists. Among the questions Hobson explores are: What are dreams? Do they have any hidden meaning, or are they simply emotionally salient images whose peculiar narrative structure refects the unique neurophysiology of sleep? And what is the relationship between the delirium of our dream life and psychosis? Originally published by Little, Brown under the title The Chemistry of Conscious States.