This volume contains a stimulating but highly semantic discussion of the physiological and psychological aspects of consciousness. The introductory chapter by Kety neatly bridges the impassable gap between consciousness and cerebral metabolism in a manner which sets the spirit of the entire symposium. There follows the usual informal give and take among the participants.
The rest of the book contains an interesting description of hypnotic phenomena by Wolberg and a chapter on experimental work, on sleep and other aspects of brain function, including dreams. This part is ably presented by Monnier. The thesis is supported that "in sleep there is a rerouting of nerve impulses rather than a profound change in energy level."