In software you can't really add people and expect to get more done, because their ability to understand the program and what's going on it would require so much investment and all their work would require so much review that you'd be more likely to slow things down.

Whether I'm at the office, at home, or on the road, I always have a stack of books I'm looking forward to reading.

We're creating this alliance, GAVI, that has helped buy the vaccines that were in the rich world but not getting to the poor kids, getting a very cheap price and figuring out the cold chain, getting the delivery right, and then funding research for new vaccines. A lot of them are coming along. We've got a meningitis vaccine out, got that through large parts of Africa. That has been a huge success.

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.

SPAM is taking e-mail, which is a wonderful tool, and exploiting the idea that it's very inexpensive to send mail.

I was announcing to the public, in 2006, that I'd be leaving Microsoft in a couple of years and focusing full-time on the foundation. That was the time at which we went back to New York and Warren [Buffett] announced these gifts to a number of foundations, with a very high percentage of it going to us and basically doubling our capacity.

While Microsoft does not share all of Oracle's ambitions for Java, we agree that it is a very valuable tool for software developers.