It is now fourteen years ago since I delivered a course of lectures for the Hibbert Trustees on the religion of the ancient Babylonians. The subject at that time was almost untouched; even such materials as were then accessible had been hardly noticed, and no attempt had been made to analyse or reduce them to order, much less to draw up a systematic account of ancient Babylonian religion. It was necessary to lay the very foundations of the study before it could be undertaken, to fix the characteristic features of the Babylonian faith and the lines along which it had developed, and, above all, to distinguish the different elements of which it was composed. The published texts did not suffice for such a work; they needed to be supplemented from that great mass of unpublished cuneiform documents with which the rooms of our museums are filled. My lectures were necessarily provisional and preliminary only, and I had to content myself with erecting a scaffold on which others might build. The time had not yet come for writing a systematic description of Babylonian religion, and of the phases through which it passed during the long centuries of its existence. Nor has the time come yet. The best proof of this is the unsatisfactory nature of the attempts that have recently been made to accomplish the task. Our evidence is still too scanty and imperfect, the gaps in it are too numerous, to make anything of the sort possible. Our knowledge of the religious beliefs of Babylonia and Assyria is at best only piecemeal. Now and again we have inscriptions which illustrate the belief of a particular epoch or of a particular class, or which throw light on a particular side of the official or popular religions; but such rays of light are intermittent, and they penetrate the darkness only to be succeeded by a deeper obscurity than before. All we can hope to do is to discover the leading conceptions which underlay the religion of Babylonia in its various forms, to determine and distinguish the chief elements that went to create it, and to picture those aspects of it on which our documentary materials cast the most light. But anything like a systematic description of Babylonian religion will for many years to come be altogether out of the question; it must wait until the buried libraries of Chaldæa have been excavated, and all their contents studied. We are but at the beginning of discoveries, and the belief that our present conclusions are final is the belief of ignorance.