Throughout his life, Le Corbusier always carried sketchbooks in which he accumulated observations, calculations, notes, architectural drawings, and sketches of works and projects. As a whole, these constitute a source of extraordinary interest. The architect"s reflections come to life, creation appears in its nascent state. In and of themselves, the sketchbooks represent a sort of fundamental "latent work," for which the finished work, whatever its mode of expression, is only a secondary outcome.