Although Leonardo da Vinci was one of the greatest artists who ever lived, his career was marked by an unusually large number of uncompleted projects and by finished works that rapidly deteriorated. Nevertheless, his influence is undoubted, and his claim to greatness rests chiefly on his drawings, which have been carefully preserved in such locations as Windsor Castle, the Louvre, the Uffizi Gallery, and the British Museum. This collection, excellently...