This revised and expanded edition of a book that first appeared in 1945 offers an inside look at the growth and spread of Christianity in the second century by providing source materials from pagan witnesses, Christian churches, and movements that became known as heretical. Reading these selections provides a first-hand sense of issues and concerns in that period. It brings the reader right into the arena in which Christianity and Christians were being discussed and provides a first-hand look at what churches were facing as the Christian movement spread. Thirty-nine sections plus a biography are included.