How are practitioners grappling with the social impacts of AI systems? In An AI Pattern Language, researchers M.C. Elish and Tim Hwang present a taxonomy of social challenges that emerged from interviews with a range practitioners working in the intelligent systems and AI industry. In the book, they describe these challenges and articulate an array of patterns that practitioners have developed in response. The inspirational frame (and title) for the project was the unique collection of architectural theory by Christopher Alexander's A Pattern Language (1977). For Alexander, the central problem is the built environment. As Elish and Hwang write, "While our goal here is not as grand as the city planner, we take inspiration from the values of equity and mutual responsibility, as well as the accessible form, found in A Pattern Language. Like Alexander's patterns, our document attempts to develop a common language of problems and potential solutions that appear in different contexts and at different scales of intervention." This collection is not intended to be comprehensive or prescriptive, but rather is an experiment in cataloguing and catalyzing. AI is not out of human control, and An AI Pattern Language calls attention to the ways in which humans make choices about the development and deployment of technology. This text was created in the spirit not of an answer, but of a question: how can we design the technological future in which we want to live'more urgent to examine real trends that will be realized within this decade.