This introduction to the focus section on “Writing the Anthropocene” examines the challenges that the entry of our species into a new geological epoch poses for the humanities in general and for literary and media theory in particular. It proposes the hypothesis that the Anthropocene can best be understood as a form of writing, a process by which humankind inscribes permanent messages into the geological, climatological, and biochemical records of our planet and is forced, in turn, to study those records for messages pertaining to its future. It discusses the relationship of the Anthropocene to the wider discourse of posthumanism and also touches upon the importance of speculative realism as well as genres like the science-fiction novel to help us conceptualize our new condition. A brief summary of each of the ten essays in the focus section follows.