Leonardo da Vinci is a member of a very small class of “transformative geniuses,” not ordinary or common geniuses, who have contributed abundantly to their fields, but rather the ones who have created or defined entire fields. In literature, no one asks, “Who was the greatest writer?” Honest debate can start at Number Two. Shakespeare, the consensus choice as greatest writer, is a member of this class of transformative geniuses. Similarly, Isaac Newton is recognized as the greatest among scientists and mathematicians; Ludwig van Beethoven, and possibly Bach and Mozart, are the transformative geniuses among composers. The most recent transformative genius the world has seen may have been Albert Einstein, a scientist like Newton – and Time Magazine’s “Man of the Century” for the 20th century. In ranking artists, one can start the debate at Number Three – a rank for which Raphael and Rembrandt are candidates, or perhaps one of the great French Impressionists, or the 20th century’s most famous artist, Picasso. The ranks of Number One and Number Two, however, are reserved for Leonardo and Michelangelo, taken in either order. These two are far above all other artists. Michelangelo lived a very long lifetime of eighty-nine years, and was productive to the end. Leonardo, on the other hand, lived sixty-seven years, and left behind just a dozen paintings. And only a half of these are incontrovertibly one hundred per cent by him. In contrast, Rembrandt painted hundreds of paintings, 57 of himself alone; van Gogh created nine hundred paintings in a period of nine years. So how can we put Leonardo at the very pinnacle? The answer is really quite simple: his dozen or so paintings include the Number One and the Number Two most famous paintings in the history of art – The Last Supper and Mona Lisa.