I watched the piles of feces go up the conveyor belt... They made their way through the machine... A few minutes later I took a long taste of the end result: a glass of delicious drinking water.

We're still missing about a dozen vaccines that will make a huge difference. For adults, we've got HIV and TB are still huge; for kids malaria is still killing a half million kids a year out of that 6 million. We probably need some vaccines, but we need a little more data to make sure we're getting the vaccines that will save the most lives.

Microsoft's only factory asset is the human imagination.

The microprocessor is a miracle.

Make sure people get educated, help out with health emergencies. Those things, the government should do. That's 96 per cent of the economy, those two sectors.

We need to cooperate globally on epidemic preparedness and prevention in the same way we are cooperating globally to stop people from getting nuclear weapons.

I think that our progress on key diseases over the next several decades is going to be pretty amazing and so I am very interested in that.