Arthur Darby Nock (1902-1963) made lasting contributions to classical scholarship and the history of religion, including the study of ancient religion, magic, and the relationship of paganism to ancient Judaism and early Christianity. Almost ninety years after its publication, his work, Conversion: The Old and New in Religion from Alexander the Great to Augustine of Hippo, serves as an introduction to what is today an entire area of research encompassing history, literature (i.e., "conversion" as a literary genre), philosophy, psychology, and theology. The present volume features essays exploring the circumstances of religious transformation not only in early Christianity but also in other ancient religions and in philosophical schools - the various converts, the means by which followers attracted adherents, and the factors influencing and limiting their success.