During the course of his lifetime Leonardo had cultivated the project of writing an organic treatise on painting, but without ever managing to fulfill this ambition. After his death his pupil Francesco Melzi compiled the Book on Painting from Leonardo's original manuscripts. The Book on Painting is divided into eight chapters: comparison of the different arts, precepts for the painter, the human figure, drapery, shadows and light, trees, clouds and the horizon. Before its publication (1651) this text widely circulated among the artists of the 16th and early 17th centuries.