I read this book and wonder where I went wrong in my career. This fellow is writing from a hotel in Italy, has a Harvard professorship and a McCarthur foundation grant, and gets to think great thoughts about the brain. He writes about consciousness from his perspective of dream and sleep research. His main idea is that the various states of consciusness can be located in a space defined by variables of activation of the brain, input modulation, and neuromodulation by serotonin, norepinephrine and acetylcholine. Acetylcholine leans the brain towards consciousness, where activation is high, and sensory gating pays attention to external stimuli; in REM sleep internal sensations predominate. His prose was a little on the purple side, and I think he made some errors in the neurochemistry and neurophysiology, but the book is handsomely designed and generally interesting. ( )

A neuroscientist's take on the subject. Uses a 3-dimensional state-space model.