Epiphanius, monastic founder and bishop of Salamis on Cyprus for almost 40 years of the fourth century, threw heart and soul into the controversies of the time and produced the "Panarion" or "Medicine Chest," a historical encyclopedia of sects and heresies and their refutations. Book I, concerned chiefly with Gnostic and Jewish Christian groups, deals with material which is also found in Nag Hammadi, other Gnostic writings, and in such patristic authors as Irenaeus and Hippolytus. Documents not available elsewhere are reproduced here. Its translation has been found useful by students of Nag Hammadi and Gnosticism, patrologists, historians of religion, church historians, and students of Judaism, .