From 1918 onward, Le Corbusier, who was not only an architect but also a painter, was engaged in conceiving and generating the idea of Purism, a pursuit he undertook in conjunction with the painter Amédée Ozenfant. Not surprisingly, paintings were their first tangible products in this field. Their reflections on the relationship between form and color led to the determination of the so-called “large gamma”: yellow and red ochres, earthy colors, white, black, ultramarine, and a few mixed colors derived from these. With the term “architectonic color,” Le Corbusier addressed the profound link between this gamma and architecture. This book is an account of a significant aspect of Le Corbusier’s oeuvre. His youthful works had been built in a then-traditional style, making use of local construction method and materials, and bearing the decoration he himself had created. However, with his Purist architecture, whose principles he formulated from 1920 onward, he embarked upon a radically different course. His buildings were constructed in reinforced concrete, finished with a layer of plaster and then completely painted. The colors of this paintwork were derived from the “gamma.” With his ideas on the polychromy of the twenties, Le Corbusier placed himself closer to Paolo Veronese than to Theo van Doesburg. Following a rift with Ozenfant in 1925, Le Corbusier entered a new architectonic path and the system of Purist polychromy gradually vanished from his work. In the 1950s, Le Corbusier gave preference to natural polychromy--the color of the material itself--above painted polychromy. Whereas polychrome painting in Purist architecture had once been an inevitable and total process, after the Second World War it was allocated a modest position as mere ornamentation.