Within recent years the subject of Ruler-Worship has attracted a great deal of attention from scholars, and much has been written upon it from various aspects, notably by those who are specialists in ancient religion. If I appear then to be trespassing I can only plead in excuse that the subject is of great, indeed of absorbing, interest for anyone who is a student of ancient civilization, and especially of the Roman Empire. What I offer here are some fruits of my reading in the ancient authors and the modern interpreters of their thought: all that can be done, of course, in short compass is to stress some results already ascertained, and to offer some observations of my own in the hope they may prove useful. But my debt to other scholars is obviously large: let me here mention with gratitude Adcock, Altheim, Bolkestein, Edson, Ferguson, Gow, Immisch, Pfister, Pippidi, K. Scott, Tarn and O. Weinreich, but above all A. D. Nock and Miss L. R. Taylor, who after Beurlier have contributed so much to advance our knowledge of ruler-cult. Sometimes I have ventured to prefer my own opinion, but I can echo the amiable Vitruvius in declaring— “neque alienis indicibus mutatis interposito nomine meo id profero corpus neque ullius cogitata vituperans institui ex eo me adprobare, sed omnibus scriptoribus infinitas ago gratias.”