This book deals with the development of popular religious and spiritual movements in Japan in the nineteenth and twentieth centuries. At present it is estimated that more than ten percent of Japan’s total population are members of so-called New Religions. While Buddhist and Shinto influences remain pronounced, there are many other features common to modern Japan’s popular religious thinking. Through the careful study of these features, classical concepts and theories of the sociology of religion are reexamined and alternatives proposed, and religion in modernity is reconsidered in the context of Japan’s cultural heritage.