Although Leonardo da Vinci's "Treatise on Painting" was not printed until the 18th century, the fragmentary manuscripts assembled by its early editors to compose it had circulated profusely in Europe and aroused the admired curiosity of artists and scholars. It is another of Leonardo's impossible undertakings, one more failure of those who, by very different paths, took advantage of their endeavor to recast all the empirical formulations and all the conceptual topics of the Renaissance, ordering them into a universal system. Every edition of the 'Treatise' must be understood with the difficulty of evoking this vision and that failure, selecting and combining texts and drawings, a difficulty that had not been successfully overcome in the existing publications in the Spanish language. The version that we present, therefore, comes to fulfill an urgent requirement of the Spanish artistic bibliography.