We have completely eradicated smallpox; we have almost eradicated polio. That's the miracle of vaccines, which is even greater than that of antibiotics.

Really advanced civilization is based on advances in energy.

Any version of Windows is going to have lots of great new things that people use and things that are tough.

It's pretty incredible to look back 30 years to when Microsoft was starting and realize how work has been transformed. We're finally getting close to what I call the digital workstyle.

I don't have a magic formula for prioritizing the world's problems.

Going out in the field, it's always enlightening to see what's working and what's not and to sit down and talk - I was with young girls in south Africa - understanding why our tools for prevention aren't being adopted, and what way may need to invent to help protect them.

The Gates Foundation has learned that two questions can predict how much kids learn: 'Does your teacher use class time well?' and, 'When you're confused, does your teacher help you get straightened out?'