Physicists have discovered that the vast majority of the universe's mass is constituted by what remains transparent. So far, this mysterious dark matter can only be traced by its gravitational effects on visible matter. Taking up this analogy, theatre scholar Andrew Sofer outlines a fresh theoretical framework and critical vocabulary for examining the invisible and how it continually structures and focuses an audience's theatrical experience. Sofer argues that we cannot understand theatre and drama without investigating whatever is not there, yet not not there on stage. Dark Matter provides an enhanced understanding of theatre's capacity to alter our perceptual field through means beside the visual-to alter others' consciousness at will-and how playwrights and other practitioners have exploited that capacity throughout theatrical history. Sofer discusses black magic in Doctor Faustus; offstage sex in A Midsummer Night's Dream; masked women in The Rover; self-consuming bodies in Suddenly Last Summer; surveillance technology in The Archbishop's Ceiling; and trauma on the contemporary stage. Each discussion pinpoints new and striking facets of drama and performance that escape sight. Taken together, Sofer's lively case studies illuminate how dark matter is woven into the very fabric of theatrical representation.