While Josef Albers' Bauhaus colleagues Klee and Kandinsky are household names, Albers himself has remained inscrutable. He is best known as the painter of the 'Homages to the Square', a series of over 2,000 seemingly tightly controlled experiments in the interaction of colour. Yet he did not begin these pictures until he was in his sixties, already several decades into his career as an artist, maker and theorist, much of it pursued in the United States following the Nazi dissolution of the Bauhaus in 1933. Drawing on extensive unpublished archival writings, documents, and illustrations, this is the first full-scale biography of one of the 20th-century's great artists. Among Albers's unpublished papers are letters from friends John Cage, Robert Rauschenberg, Richard Serra, and Eva Hesse, as well as fans and collectors ranging from the composer Virgil Thomson to the cartoonist Saul Steinberg. If his network of influence was surprisingly wide, so too, were his interests.