Porphyry’s Against the Christians was the most hard-hitting, incisive, and lengthy critique of Christianity that the ancient world ever knew. Itwas so dangerous that three Christian emperors wrote decrees ordering it to be burned. The Christians succeeded in destroying it, but they did not destroy—or seek to destroy—the fragments and traces of the work in Christian authors themselves. Thus testimonies and fragments of Porphyry’s great work survive. This is the material translated and commented upon in this book. It corrects the errors and massive gaps of R. J. Hoffmann’s 1994 translation, and makes a reliable Porphyry readable for a new generation.