Eric Osborn's book presents a major study of Ireneaus, bishop of Lyons, who attacked Gnostic theosophy with positive ideas as well as negative critiques. Ireneaus' combination of argument and imagery, logic and aesthetic, was directed to a new document, the Christian bible. Dominated by a Socratic love of truth and a classical love of beuty, he was a founder of western humanism. Erasmus, who edited the first printed edition of Ireneaus, praised him for his freshness and vigour. He is today valued for his splendid aphorisms, his optimism, love of the created world, evolutionary view of history, theology of beauty and humour. Why have two millennia of European culture been so creative? Ireneaus points to the sources: Greek ways of thinking and the Christian bible. Ireneaus' thought is complex, yet infinitely rewarding to the critical reader, and this full study of it will be of interest to theologians, historians of ideas, classicists, scientists and students.