“An Episode of Cathedral History”: the very title promises us a study in the synchronic and the diachronic, as a few select persons inherit and respond to a structure designed to bear witness to all of human history. And a tale of the uneasy fortunes of communal history and memory is exactly what M. R. James (1862–1936) supplies, though (as we might expect from a distinguished medievalist who became one of the masters of the ghost-story genre) whatever social and aesthetic lessons we may learn are to be gained only after serious consideration of the scholarly backdrop of a kind of writing the author once characterized as “ghost stories of an antiquary.” Our purpose in this essay, then, is to investigate the complexity of these inspirations and, further, to offer an interpretation of how they may be understood to connect in the larger architecture of James's fiction. In particular, we argue that two very different kinds of “mysteries” shape this ghost story. The first of these is Dickens's The Mystery of Edwin Drood and its connections to the very specific architectural history of Rochester Cathedral. The second is the genre of the “mystery play,” a form that in James's day was understood to have evolved out of church rituals built into the very fabric of the cathedral. These mysteries may be understood as most concretely linked by James's curious creation of a plain, empty altar tomb to house his horror – an object that stands at the center of medieval drama, of Rochester cathedral history, and, of course, of this ghost story itself.