City and regional planners talk constantly about the things of the world from highway interchanges, retention ponds, and affordable housing units to zoning documents, conference rooms, and consultants’ reports. The material world of planning is acknowledged but insufficiently theorized. In Planning Matter, Robert Beauregard offers a new materialist perspective on planning practice that relies heavily on actor-network theory and science and technology studies to reveal the many ways in which the non-human things of the world mediate what planners say and do. In order to emphasize the importance of planners constantly imagining themselves “in the world,” the argument is illustrated with numerous empirical examples from planning practice in the United States. The result is a theoretical approach that recognizes the vibrancy of non-human matter and the fact that planners neither act alone nor solely with other human beings.