Struggles to escape form as a manifestation of various norms and constraints are as old as architecture itself. But the formless is also increasingly in the air today, explicitly as in discussions of the "formless" quality of the city, and implicitly in talk of atmospheric buildings, randomized structures, and the dematerialization (or increased mediation) of architecture. No doubt part of its appeal lies in the fact that the formless is frequently found at the intersections between architecture and other fi elds, from art to ecology or engineering. Nevertheless, the formless has not yet been theorized rigorously in architecture. It seems to underpin a wide range of tendencies that have not yet been connected, or even explicitly acknowledged or identifi ed. This book represents a fi rst step toward this articulation.