This book aims at revealing the connection between Leonardo, Judaism, and Kabbalah. This link is disclosed by analyzing what can be considered his Sacred Geometry Studies (exemplified in the Vitruvian Man), his artistic techniques involving the use of light, and what we believe to be his hidden signature: the use of the decorative pattern of knots, and Solomon’s Knot in particular. Together with the countless Hebrew letters hidden in his paintings, drawings, and notebooks, these tools were combined for the first time to reveal the real code of Leo-nardo da Vinci.