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.

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.

The Internet is the easiest thing to get into. To be an Internet retailer, you just get that URL.

I like to read general biology - things about the immune system and advances in that area - because it lays the foundation for my part of the dialogue at the foundation about what things we ought to pursue.

I have $100 billion... You realize I could spend $3 million a day, every day, for the next 100 years? And that's if I don't make another dime.

Nuclear energy, in terms of an overall safety record, is better than other energy.

Microsoft does not dominate the software industry by any stretch of the imagination. We have lots of very able competitors who keep us constantly vigilant, and sometimes they beat us to the punch. Microsoft's success to date is based solely on the fact that people like Microsoft software.