What is it that makes humans predisposed to believing in the unknown, the supernatural or higher beings? In this study, Brian Hayden takes a brave step towards defining the basic principles of religion, and its evolution, from hunter-gatherers to early Christianity. He begins by differentiating between traditional religions which are based on oral learning or experience, and those based on texts, scriptures and codes. From here, he examines the ideas and values which are termed `religion' and argues that they are directed by ecological factors and emotional foundation by which humans are open to enter `sacred ecstatic states' through procedures such as fasting, meditation, sex and trance. Beginning with early hunter-gatherers and concepts of shamanism and early ritual, Hayden addresses the debate over Neanderthal rituals, discusses the emergence of megalith building, mystery and fertility cults, and explores the religions of early states and empires with a broad range of representative examples. `A broad and uniquely archaeological perspective on the evolution of religious behaviour from prehistoric times to the present.'