This book is rooted in a conception of early Christiani ty as a social world in the making. It seeks to explore the relevance of this conception for certain basic issues-the relationship between religion and social status, the enthusiastic character of the earliest Christian communities, their gradual transformation into a formidable religious and social institution, and the emergence of Christianity as the dominant religion of the later Roman Empire. Within this general framework, the approach will be comparative and theoretical: theoretical in the sense that I will make use of explanatory models drawn from the social sciences, and comparative in that much of the evidence for these models is based on studies of non-Christian religious movements.