What is it that allows human beings to think the way we do? What enables us to communicate with one another through the use of speech? Is the difference between Homo sapiens and other apes simply a matter of degree or are we unique and discontinuous from other species? Michael C. Corballis argues that this century-old debate lies in the fact that humans are the only primates that are predominantly right-handed, a sign of the specialization of the left hemisphere of the brain for language. Surveying the current views of evolution using evidence from archaeology, linguistics, neurology, and genetics, Corballis takes us on a fascinating tour of the origins and implications of the structure of the human brain, accounting for the dominance of humanity over all species.