In April 1937, the Museum of Modern Art in New York hosted an exhibition that served as a catalyst for the appropriation of prehistoric rock art in postwar abstract painting. With the title "Prehistoric Rock Pictures in Europe and Africa", it displayed a range of copies from the influential collection of the German ethnologist Leo Frobenius. Largely disregarded in modern American art history up until now, this book highlights the importance of this exhibition to artists such as Josef Albers, Adolph Gottlieb, David Smith, and The American Abstract Artists group, who sought inspiration from the prehistoric images' primordial creativity. With a transnational scope, this book reveals new facts about the connections between Paris and New York, and the importance of communication and collaboration between them for these artists. In doing so, Seibert shows that this debate was about more than just legitimizing abstract art forms from the past, but about recognizing an autonomous American abstract art. Presenting unseen archival material, letters, and exhibition documentation, Prehistoric Pictures and American Modernism offers a new reading of the development of modern American abstraction, and will hold an important place in the historiography of the movement, its global traditions, and its legacy.