The Mona Lisa, to me, is the greatest emotional painting ever done. The way the smile flickers makes it a work of both art and science, because Leonardo understood optics, and the muscles of the lips, and how light strikes the eye - all of it goes into making the Mona Lisa's smile so mysterious and elusive.

Physics should represent a reality in time and space, free from spooky action at a distance.

The reality distortion field was a confounding mélange of a charismatic rhetorical style, indomitable will, and eagerness to bend any fact to fit the purpose at hand.

If you act like you can do something, then it will work.

The childhood that Paul and Clara Jobs created for their new son was, in many ways, a stereotype of the late 1950s. When Steve was two they adopted a girl they named Patty, and three years later they moved to a tract house in the suburbs.

I think Leonardo da Vinci teaches us the value of both being focused on things that fascinate us but also, at times, being distracted and deciding to pursue some shiny new idea that you happen to stumble upon. Balancing intense focus with being interested in a whole lot of different things is something that we have to do in the Internet age.

When you write biographies, whether it's about Ben Franklin or Einstein, you discover something amazing: They are human.