When did humans develop spiritual thought? What is religion's evolutionary purpose? And in our increasingly secular world, why has it endured? Every society in the history of humanity has lived with religion. In this book, evolutionary psychologist Professor Robin Dunbar tracks its origins back to what he terms the 'mystical stance' - the aspect of human psychology that predisposes us to believe in a transcendent world, and which makes an encounter with the spiritual possible. As he explores world religions and their many derivatives, as well as religions of experience practised by hunter-gatherer societies since time immemorial, Dunbar argues that this instinct is not a peculiar human quirk, an aberration on our otherwise efficient evolutionary journey.