1. An earlier volume in this series presented a translation of the Proof of the Apostolic Preaching,1 one of the two works of Irenaeus which have survived in their entirety. With this volume the series begins publication of Irenaeus’s principal work, his Exposé and Overthrow of What Is Falsely Called Knowledge. It is this work, commonly called Adversus haereses, or, Against the Heresies, which establishes Irenaeus as the most important of the theologians of the second century and merits