The notion of play occupies a special place in the history of modern art and architecture. Theorized in the 19th century by Friedrich Froebel as fundamental to the process by which children learn, play would form the basis of Froebel’s kindergarten, now a model for early childhood education worldwide. The aesthetic intensity of Froebel’s program would likewise contribute to a variety of radical educational projects in the 19th and 20th centuries, including the Bauhaus. Later, Johan Huizinga’s seminal meditation on the “play element in culture,” Homo Ludens, would provide an intellectual foundation for a number of 20th century aesthetic and political movements, among them the Situationist International. Finally, a generous focus on play has recently reemerged within the discourse on a range of 21st century art and design practices, characterized by a shared focus on participation and performativity, as in the work of Rirkrit Tiravanija and Lottie Child. This course, then, explores the place and problem of play in three ways: as a critical framework for understanding the aesthetic qualities of the human environment; as a mode of experience, giving meaning to that environment; and as a working method employed by artists and architects as a specific form of practice.