The genius of capitalism lies in its ability to make self-interest serve the wider interest. The potential of a big financial return for innovation unleashes a broad set of talented people in pursuit of many different discoveries. This system, driven by self-interest, is responsible for the incredible innovations that have improved so many lives.

We all learn best in our own ways. Some people do better studying one subject at a time, while some do better studying three things at once. Some people do best studying in structured, linear way, while others do best jumping around, surrounding a subject rather than traversing it. Some people prefer to learn by manipulating models, and others by reading.

It is a high bar to say that it's more fun than working on software because the work at Microsoft that both Melinda [Gates] and I did was thrilling. We were making breakthroughs and empowering people.

The ideal thing would be to have a 100 percent effective AIDS vaccine. And to have broad usage of that vaccine. That would literally break the epidemic.

I keep bumping into that silly quotation attributed to me that says 640K of memory is enough. There's never a citation; the quotation just floats like a rumor, repeated again and again.

The malaria parasite has been killing children and sapping the strength of whole populations for tens of thousands of years. It is impossible to calculate the harm malaria has done to the world.

All lives have equal value. And so you say, 'why do poor children die when other children don't? Why do some people have enough nutrition or reasonable toilets and other people don't?' So those basic needs that, through innovation, actually it's very affordable to bring them...to everyone.