As wide-ranging as it is deep, and as entertaining as it is informative, the latest offering from UC–Santa Barbara neuroscientist Gazzaniga (The Ethical Brain
) will please a diverse array of readers. He is adept at aiding even the scientifically unsophisticated to grasp his arguments about what separates humans from other animals. His main premise is that human brains are not only proportionately larger than those of other primates but have a number of distinct structures, which he explores along with evolutionary explanations for their existence. For instance, a direct outgrowth of the size and structure of the human brain, along with their origins in the complexity of human social groups, was the development of language, self-awareness and ethics. (Gazzaniga offers some surprising comments on the evolution of religion and its relation to morals.) Throughout, Gazzaniga addresses the nature of consciousness, and by comparing the intellectual capabilities of a host of animals (chimps, dogs, birds and rats, among others) with those of human babies, children and adults, he shows what we all share as well as what humans alone possess. (July)