Saint Irenaeus was the first great Christian theologian. Born in Asia Minor in about 130 A.D., he became Bishop of Lyons and died as a martyr early in the third century. His main work, Adversus Haereses (Against the Heresies), is as relevant today as it was eighteen hundred years ago. It is a critique of Gnosticism, the 'anti-body' heresy, which, far from dying out, continues to flourish as the main threat to the Christian faith in our own...