One of the world's foremost scholars of evolution tackles one of its essential mysteries: why we believe.Our species diverged from the great apes six to eight million years ago. Since then, our propensity toward spiritual thinking and ritual emerged. How, when, and why did this occur, and how did the earliest, informal shamanic practices evolve into the world religions familiar to us today? What is the evolutionary purpose of religion, and are some individuals more inclined than others to be religious?In How Religion Evolved, Robin Dunbar explores these and other questions, mining the distinctions between religions of experience--as practiced by the earliest hunter-gatherer societies--and doctrinal religions, from Judaism, Christianity, and Islam to Zoroastrianism, Hinduism, Buddhism, and their many derivatives.Examining religion's origins, social functions, its effects on the brain and body, and its place in the modern era, Dunbar offers a fascinating and far-reaching analysis of the quintessentially human impulse to believe.