Koln: Wallraf-Richartz Museum, 1971. Fifth and last edition. 92 artists and 209 color plates. Large thick quarto. Published in conjunction with the landmark exhibition of the contemporary art collection of Dr. Peter Ludwig at the Wallraf-Richartz Museum in Cologne. From Albers to Warhol. Text in German. Numerous tipped-in plates and acetate overlays with corresponding images of artists and reproductions of their works. One of the best-known and most important documents about modern art published in the sixties. faint tidemark to a number of pages at the bottom, else near fine in heavy acetate wrappers screw bound into a plastic binding.