Celebrated as a painter and engineer during his lifetime, Leonardo da Vinci was the very embodiment of the Renaissance Man. But few guessed at the extent of his scientific investigations and experiments. In a vast collection of notebooks (over 5,000 pages), Leonardo meticulously detailed his research on optics, mechanics, astronomy, and anatomy. He kept his findings hidden for fear his ideas would be stolen. Had they been shared or published, they might well have changed the course of scientific discovery, for they prefigured the work of Newton, Galileo, and Kepler. Instead, after Leonardo's death, his papers were lost to the world for nearly 200 years; some were never recovered. Using newly available documents, Michael White illuminates Leonardo's groundbreaking achievements and weaves together the elements of his life and times-his unhappy childhood, his homosexuality, his relationship with everyone from Machiavelli to Cesare Borgia to Michelangelo.