More than fifty years have now passed since M. R. James published his British Academy lectures on the Apocalypse in medieval art under the title The Apocalypse in Art (London 1931). As we approach the coming of the second millennium, the last few decades have witnessed an exponential rise in the number of scholarly publications dealing with apocalyptic imagery in the Middle Ages, particularly with regard to illuminated manuscripts. An increasing number of scholars entering this fascinating field of research each year has created a genuine need for more direct and convenient access to the wealth of material that now exists on this rich and complex subject. The project for the present census and bibliography of manuscripts containing Apocalypse illustrations, c. 800–1500, was developed from the authors' individual research and was prompted by the recognition that every medievalist who wishes to work with this material must first invest considerable time and energy in gathering this sort of data and bibliography before any serious research can begin. Our compilation is therefore designed to serve primarily as a helpful starting point for scholars from all disciplines in medieval studies with a research interest in some aspect of medieval Apocalypse illustrations.