In ninth grade, I came up with a new form of rebellion. I hadn't been getting good grades, but I decided to get all A's without taking a book home. I didn't go to math class, because I knew enough and had read ahead, and I placed within the top 10 people in the nation on an aptitude exam.

When I say "miracle" I mean a kind of thing like a computer on a chip, or the internet, or the cellphone, that are really quite miraculous. Most people would not have predicted them, and their effect has been very, very dramatic.

I know that historically our foundation has had great relations with all the administrations.[Bill] Clinton administration did a lot of outreach. The greatest rise in U.S. foreign aid was under the [George] Bush administration, that's where we got the AIDS initiative, which is called PEPFAR.

Like my friend Warren Buffett, I feel particularly lucky to do something every day that I love to do. He calls it "tap dancing to work."

Software is definitely engineering. It's different in that we take on novel tasks every time. It's not like building a certain bridge that is virtually identical to some previous bridge or some previous building.

If you go back to 1800, everybody was poor. I mean everybody. The Industrial Revolution kicked in, and a lot of countries benefited, but by no means everyone.

Take agriculture, where we haven't done much, or sanitation; saying, "okay, we will be able to make a really huge effort there." It really energized the foundation and half of what we've gotten done in this last decade is because Warren [Buffett] trusted us.