This volume cannot claim to be written in the popular style adopted in some other volumes of the series, for the simple reason that the subject scarcely admits of being popularised. At the same time I have tried to make the book readable, and to refrain as far as possible from undue technicalities of philosophical and theological language. It has been my aim to avoid on the one hand the Scylla of catering for a public which no art or device will ever induce to concern itself about Greek Patristic Theology, and, on the other, the Charybdis of scholastic pedantry. Rightly or wrongly; I am convinced that my task will be most usefully accomplished by furnishing a brief introduction to the study of a subject on which, in English at least, there are not too many easily accessible helps. In view of the impossibility of assuming any very intimate knowledge of Origen's writings on the part of the general reader, or even of the average theological student, I have further deemed it best, while not refraining from criticism where it seemed called for, to aim at being expository rather than critical.