What imaginaries, tropes, and media have shaped how we theorise? 'The Mark of Theory' argues that inscription constitutes one of the master metaphors of contemporary theory. As a trope that draws on a wide array of practices of marking, from tattooing to circumcision, from photographic imprints and phonographic grooves to marks on a page, inscription provides an imaginary that orients and irritates theoretical thought. Tracing inscriptive imaginaries from the late 19th century to today, the work offers a wide-ranging conceptual genealogy of contemporary thought.