Yves Klein: Air Architecture is not about Leap Into the Void, the 1960 photograph of Yves Klein diving out the second story of a building. Rather, it presents the architectural projects and theories of the French conceptual artist in the context of current tendencies toward immateriality in architecture, design, and art. This volume includes reproductions of drawings and other works from the Yves Klein Archive in Paris, as well as essays offering both historical and contemporary perspectives on the artist's work. This will be the first publication and accompanying exhibition focused solely on this body of Klein's work. Also included are the first English translation of Klein's lecture at the Sorbonne in 1959, along with related writings. Essays articulate the importance of Klein's work on the subject of immateriality and cite the evolution of this idea from the 1950s through today. A visual essay illustrates this evolution with examples of works by late modern and contemporary architects, designers, and artists.