This catalog concentrates on one of Mondrian’s great formal and expressive inventions: the diamond-shaped painting. These canvases occur in almost every phase of his mature career, from the first four, which initiate his abstract work, to the last picture, Victory Boogie-Woogie, where Mondrian was still proposing new ideas. The prominence of these works, classic images of modern art, is remarkable in light of the fact that there are only 16 known paintings in the format, and of these, less than half are in the stylistic vocabulary we generally identify with Mondrian. The catalog includes an essay on several aspects of the diamond paintings and in-depth studies of two of these works. Entries for the works include provenance information and exhibition history.