Leonardo da Vinci was comfortable being illegitimate, gay, a misfit, a heretic. But he also respected other people. He didn't get into disputations. He was a genius but he had a certain humility. In his notebooks you see lists of people he wanted to grill about things like how the water diversions in Milan work; he was always interested in learning from other people.

Throughout his life, Albert Einstein would retain the intuition and the awe of a child. He never lost his sense of wonder at the magic of nature's phenomena-magnetic fields, gravity, inertia, acceleration, light beams-which grown-ups find so commonplace. He retained the ability to hold two thoughts in his mind simultaneously, to be puzzled when they conflicted, and to marvel when he could smell an underlying unity. "People like you and me never grow old," he wrote a friend later in life. "We never cease to stand like curious children before the great mystery into which we were born.

Sometimes, to relieve stress, he would soak his feet in the toilet, a practice that was not as soothing for his collegues.

If you want to be a great American, you have got to understand Ben Franklin, Thomas Jefferson, George Washington, how the American Revolution happened. I think if you want to be a good citizen of the digital age, it helps to feel comfortable with both the people and the ways of thinking that created the digital revolution.

Most innovation comes from people working together, collaborating in teams.

I think one problem we've had is that people who are smart and creative and innovative as engineers went into financial engineering.

I think the biggest innovations of the twenty-first century will be the intersection of biology and technology. A new era is beginning, just like the digital one was when I was his age.