You have to be willing to see that sometimes the governments of these poor countries don't come through. You have to think about that as a constraint. How do you help them be better? How do you come up with things that actually work, even in those tough situations.

Success is a lousy teacher. It makes you think you know what you're doing.

The death of a child is an incredible tragedy all over the world. Back in 1990, about 12 percent of children were dying before they reached the age of 5.

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Well depending on the government, you either work through the government, which is ideal, because then you're strengthening their capabilities, or you work through the non-governmental organizations. It's never easy, and you know, it's just about the very basics of health. This is not hospitals. This is just primary health care [in Africa], the most simple things, and even so, getting the supplies out, getting the trained workers there.

So not only are we saving lives now, we're creating the incentive for the breakthroughs that over the next generation will mean we can take AIDS, malaria and TB and bring those numbers dramatically down.

Countries which receive aid do graduate. Within a generation, Korea went from being a big recipient to being a big aid donor. China used to get quite a bit of aid; now it's aid-neutral.