Taking a look back, one big reqret is, I left Harvard with no real awareness of the awful inequities in the world. The appalling disparities of health and wealth and opportunity that condemned millions of people to the lives of despair. I learned a lot here at Harvard about new ideas and economics, and politics. I got great exposure to the advances being made in the sciences. But humanities greatest advances are not in its discoveries, but in how those discoveries are applied to reduce inequity.

Digital technology has several features that can make it much easier for teachers to pay special attention to all their students.

The government is somewhat inept, but the private sector is inept in general. How many companies do venture capitalists invest in that go poorly? By far most of them. However, every once in a while a Google or a Microsoft comes out, so people keep giving them money.

Today, we take the risk of nuclear war quite seriously, climate change not so much and epidemics least of all. But no single country, not even the United States, is well prepared. And even if one country is doing the right things to protect itself, it has to be a global thing.

Vaccination is one of the easiest things on the way to development. It's much easier than roads and a great education system. It's very basic. It's one of the first things you want to get right.

Like any well designed software product, Windows is designed, developed and tested as an integrated whole.

When you develop software, the people who write the software, the developers are the key group but the testers also play an absolutely critical role. They're the ones who ah, write thousands and thousands of examples and make sure that it's going to work on all the different computers and printers and the different amounts of memory or networks that the software'11 be used in. That's a very hard job.