The Vitruvian Man is a universal image. At the end of the 1st century BC, the treatise De architectura was written, causing Vitruvius to pass into history. The part dedicated to the proportions of the buildings shows the famous principle of the harmony of each body, which adheres to precise rules, numbers, and canons. This simple principle of ancient art surfaced again during the Renaissance: Leonardo and his contemporaries knew the theme of the canon, which, according to the Vitruvian text, regulated proportions in the figurative arts. Several authors have proposed a graphic version of the Vitruvian canon, but Leonardo’s solution, conserved in the Gallerie dell’Accademia in Venice, is decisively the most correct, the most refined, and, at the same time, the most original. It was, once again, the desire to experiment that led Leonardo to his Vitruvian Man, one of the most famous images in the world. The result of his meticulous research is given by the dual position of the human figure, the one standing and with arms extended, inscribed perfectly in the square, and the other outstretched, with arms and legs spread apart, touching the circumference of the circle. The original solution that Leonardo reached is the one that is most correct, the only one, for example, that respects the Vitruvian canon of the center at the navel. Leonardo arrived to this refined model through his personal and utterly modern way of carrying out research, through tests and experiments that led him to propose, in some anatomical details, measures different from those of the canon, as he himself writes in the text accompanying the drawing. His Vitruvian Man is in fact the most correct, but not an exact reproduction. It is a new, updated version, the result of the desire to know, to experiment, to improve.