Nigeria has moved into low-middle-income, but their north is very poor, and the health care systems there have broken down.

I'm sorry that we have to have a Washington presence. We thrived during our first 16 years without any of this. I never made a political visit to Washington and we had no people here. It wasn't on our radar screen. We were just making great software.

I think when smallpox was eliminated, the whole world got pretty excited about that because it’s just such a dramatic success.

The most important work I got a chance to be involved in, no matter what I do, is the personal computer... I even knew not to get married until later because I was so obsessed with it. That's my life's work.

The need to communicate effectively with your customers will come up again and again.

With nuclear weapons, you'd think you would probably stop after killing 100million. Smallpox won't stop. Because the population is naïve, and there are no real preparations. That, if it got out and spread, would be a larger number.

Contrary to Piketty’s rentier hypothesis, I don’t see anyone on the [Forbes 400 list of the wealthiest Americans] whose ancestors bought a great parcel of land in 1780 and have been accumulating family wealth by collecting rents ever since. In America, that old money is long gone - through instability, inflation, taxes, philanthropy, and spending.