Most thinking about international relations ignores religion. But in fact, religious influences have always been more important than most people realize -- and today, that importance is only growing. This collection of essays provides a useful survey of how religion, particularly Christianity and Islam, has affected modern international politics. Scott Thomas disputes the presumption that religion and cultural pluralism cannot be reconciled in international society and argues that to see today's religious movements as part of a fundamentalist-driven clash of civilizations misses their role in a broader struggle to find alternative paths to modernity. Other authors challenge the assumption that the politicization of religion is inevitably a threat to international security. Overall, the book is short on empirical explorations of contemporary religious disputes, but its message is sensible: diplomats and scholars must engage, not ignore, global religious movements.