We have two other countries, Pakistan and Afghanistan - again it's the instability that is a problem there. So over the next several years, we expect to drive the number of [polio] cases back down to zero because that is likely to be the second disease after smallpox that we completely eradicate.

Globalization has made copper and other minerals more valuable, and Ghana and Kenya have recently discovered mineral resources.

[AIDS ] is not a short-term emergency but it is something that, just like smallpox was many decades ago, we should aim for complete eradication.

Anyway, the US, as in most issues, is the best, has the best capability to lead, and really needs to lead. It doesn't [mean] that other countries won't pick different tacks and emphasize different things. In aggregate, they're almost half of the energy R&D. Europe, China, Japan - it's very important that they come along and contribute to these things.

I have a nice office. I have a nice house... So I'm not denying myself some great things. I just don't happen to have expensive hobbies.

Microsoft has had many, many successful products. I'm committed to one company. This is the industry I've decided to work in.

In fact, batteries haven't improved over the last 100 years as much as they would need to in order to make that happen. So I'm invested in a lot of battery companies - and there's a lot that exists I'm not in. They're all having a tough time achieving it.