""What is it like, to be a chimpanzee?"" asks Calvin, a neurobiologist at the University of Washington, in the first chapter of this fascinating history of the mind. While humans and other primates share many cognitive abilities, an accumulation of qualitative differences in perception, learning and time sense add up to an unbridgeable gap, he says. Tracing human evolution from the first upright hominid through tool making and on to structured thought and hypotheses about the future, Calvin (How Brains Think; A Brain for All Seasons) offers readers a concise, absorbing path to follow. Trying to imagine the thoughts and lives of early humans is not much different than trying to know what it's like to be a chimpanzee, as it turns out. Eventually, Calvin reveals how our evolving brains might have developed such bizarre abstractions as nested information, metaphors and ethics, thus paving the way for consciousness as we know it. He postulates the ""mind's Big Bang"" as tied to the development of language, offering as support the nativist mind theories of Steven Pinker and Noam Chomsky. Presented with a pleasing blend of philosophy, neuroscience and anthropology, Calvin's ideas are accessible for anyone interested in a scientific look at how our brains make us different from chimpanzees. He adds a cautionary note, too: as human brains get smarter--and as our guts stay primitive and our technology skyrockets--we must get better about""our long-term responsibilities to keep things going.""