The visual arts were of great importance for Pierre Boulez, whether through particular works of art or through encounters with the artists themselves. Indeed, his thinking and writing were nourished by painting and drawing (and to a lesser extent, sculpture, photography and film). It was through the attention he gave to the work of the painter, Paul Klee, that Boulez made explicitly clear the fundamental principle underpinning his approach: an object of reflection must be transcended and considered in terms of an entire network of relationships, such that a distance is always kept from the object under consideration. This comparative ‘ethic’, emblematic of Boulez’s thinking, found its most fertile ground in painting and an unequalled ambassador in Klee. The chapter explores Boulez’s engagement with the work of Klee as well as that of de Staël, Mondrian, Kandinsky, Miró, Vieira da Silva and other significant visual artists.