'What am I to believe?' is perhaps the fundamental question of human existence. It is unlikely that most people reach the end of their lives without wondering what it has all been for and what happens next. But the question of belief is more than just academic, since what people believe is now more critical than ever. As G R Evans shows, an ignorance of the history of beliefs can leave individuals susceptible to the influence of extreme ideas, and unsure how to put them into context and judge their validity. In all religions, not just Islam and Christianity, that is precisely how sects and cults get a grip. This book shows how ethical questions fit together, and how great historical debates and decision-making - whether about religious conflict, or theodicy, or questions of authority - shed light on some of the great moral challenges facing the religions today. Concentrating especially on the Christian tradition, Evans shows how the history of religious debate can help us to understand the nature of current misunderstandings and division over belief, a crucial step for people of all faiths in the new century.