This is the book in which Julian Jaynes presents his theory that consciousness is only a few thousand years old, and that all the civilizations preceding the late second millennium B.C. consisted of unconscious men who were blindly obeying what they perceived to be the voices of gods.
Julian Jaynes is vastly underrated as a thinker. His theory is revolutionary, entirely supported by the evidence, and obvious once you're aware of it. The ideas in this book are to psychohistory what the ideas in Origin of Species were to biology.
Jaynes is also an excellent writer, who communicates his ideas in an understandable and well organized format. The Origin of Consciousness in the Breakdown of the Bicameral Mind can be read by the layman, which is fortunate, because it should be read by everyone.