"El tratado de la pintura" by Leonardo da Vinci is a collection of writings gathered from his notebooks between 1482 and 1499. Originally compiled by his heir Francesco Melzi and first published in abridged form in 1651, this treatise argues that painting is a science. Leonardo examines facial expressions, human emotion, and natural observations, including his famous branching rule about tree proportions. Drawing from earlier writers like Leon Battista Alberti, these manuscripts showcase Leonardo's scientific approach to understanding and teaching the art of painting.