Media is a kind of gatekeeper, connecting disparate entities and shielding them from one another at the same time. When we speak of media, we often refer to those entities themselves--to persons, organizations, artifacts, signals, and inscriptions--referencing directors, artists, newspapers, films, iPhones, paper, ink, notes, beats, color, and soundwaves. But as the middle or between, the essence of media itself seems to be distributed across the mix of entities involved, and its location and agency are hard to pin down. This new anthology takes stock of our empirical and historical...