Ornstein's early writings on right brain/left brain differences led to a veritable explosion of research and writing on the subject. In this book he's written an excellent summary of the current state of our understanding: although it's clear that the halves of the brain have different areas of specialization, he emphasizes strongly that they need to work together to enable us to function fully as human beings. He's bemused (and sometimes annoyed) at the popular tendency to romanticize the right brain as the seat of creativity and denigrate the left brain as an unimaginative literalist; the facts show that both halves are involved in such complex human activities as listening to music and understanding jokes. His summary of the 19th-century debates on brain functioning was very useful and informative. And his conclusion that psychology needs to pay more attention to the various ways human beings have pursued spiritual development over the millennia is, I think, a very timely reminder: psychology has tended to dismiss this behavior as "superstition," but, as other writers have pointed out (e.g., Epstein's "Thoughts Without a Thinker"), it has as much to do with developing the full power of your mind as with addressing something "out there." Ornstein writes clearly and humorously, and the book packs an amazing amount of knowledge into its rather brief length.