But the improvements will happen faster and last longer if we can channel market forces, including innovation that's tailored to the needs of the poorest, to complement what governments and nonprofits do. We need a system that draws in innovators and businesses in a far better way than we do today.

Vaccines are a miracle; they're fantastic. Anything that makes people hesitate to give their children these vaccines according to the recommended schedule creates risk. Risk for the children who don't get vaccinated and risk for children, some of whom don't have an immune system, so they're benefiting from the fact that the community protection means the disease doesn't get to them.

I believe that every life is valuable. That we can make things better. That innovation is the key to a bright future. That we're just getting started.

We need to look at less obvious paths, things like the wind in the jet stream, which is very high up. The material science of what type of kite string you would need to connect up to that. That's still at the basic research level.

The Gates Foundation has learned that two questions can predict how much kids learn: 'Does your teacher use class time well?' and, 'When you're confused, does your teacher help you get straightened out?'

Instead of buying airplanes and playing around like some of our competitors, we've rolled almost everything back to the company.

You wish that you could move more rapidly and you have setbacks. You know, the AIDS epidemic was a huge setback for Africa, and it's only through generosity that we've avoided that just completely crippling an entire generation there.