How did the movement founded by Jesus transform more in the first seventy-five years after his death than it has in the two thousand years since? This book tells the story of how the Christian movement, which began as relatively informal, rural, Hebrew and Aramaic speaking, and closely anchored to the Jewish synagogue, became primarily urban, Greek speaking, and gentile by the early second century, spreading through the Greco-Roman world with a mission agenda and church organization distinct from its roots in Jewish Galilee. It also shows how the early church's witness can encourage the church today.