Eradications are special. Zero is a magic number. You either do what it takes to get to zero and you're glad you did it; or you get close, give up and it goes back to where it was before, in which case you wasted all that credibility, activity, money that could have been applied to other things.

China is certainly an important player in the global economy, and a widespread AIDS epidemic would threaten that growth.

The nuclear approach I'm involved in is called a traveling-wave reactor, which uses waste uranium for fuel. There's a lot of things that have to go right for that dream to come true - many decades of building demo plants, proving the economics are right. But if it does, you could have cheaper energy with no CO2 emissions.

The finest pieces of software are those where one individual has a complete sense of exactly how the program works. To have that, you have to really love the program and concentrate on keeping it simple, to an incredible degree.

A great lathe operator commands several times the wage of an average lathe operator, but a great writer of software code is worth 10,000 times the price of an average software writer.

Philanthropy should be voluntary.

When making choices, or setting policies about the economy, education or medicine, society is best served by electing people who are particularly hardworking, intelligent and interested in long-term thinking.