The unique Renaissance Man, Leonardo da Vinci, was something of an enigma. He was a painter who painted relatively few paintings, an architect who built no buildings and a sculptor from whom no works remain. He was primarily a theoretician who was willing to test his sometimes wild and improbable ideas. What do his sketches and paintings have to tell us about how he viewed the world? And how can we learn from them about the way this great man would approach the sometimes unanticipated challenges that face humanity today?