In spite of the debate about secularization or de-secularization, the existential-bodily need for religion is basically the same as always. What have been changed are the horizons within which religions are interpreted and the relationships within which religions are integrated. This book explores how religions continue to challenge secular democracy and science, and how religions are themselves being challenged by secular values and practices. All traditions - whether religious or secular - experience a struggle over authority, and this struggle seems to intensify with globalization, as it has brought people around the world in closer contact with each other. In this book internationally leading scholars from sociology, law, political science, religious studies, theology and the religion and science debate, take stock of the current interdisciplinary research on religion and open new perspectives at the cutting edge of the debate on religion in the 21st century.