Business isn't that complicated. I wouldn't want to put it on my business card.

The scientific understanding of some of these [childhood] diseases is advancing quite rapidly. There's some things like premature birth or nutrition, first day deaths that we need a lot more insights so that we can build the tools to solve those problems.

Even when things are stable, that's not easy [to work in Africa] because there are not roads, and the weather is tough, the education system hasn't been there. But this is how you get great countries, is step by step.

Microsoft has long hired based on IQ and "intellectual bandwidth."

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 next time someone tells you we can trim the budget by cutting aid, I hope you will ask whether it will come at the cost of more people dying.

People everywhere love Windows.