America and Japan are the two leading world economies in terms of technology and innovative products. And in software, information-age technology and biotechnology the U.S. has an amazing lead.

This social-networking thing takes you to crazy places.

Contrary to Piketty’s rentier hypothesis, I don’t see anyone on the [Forbes 400 list of the wealthiest Americans] whose ancestors bought a great parcel of land in 1780 and have been accumulating family wealth by collecting rents ever since. In America, that old money is long gone - through instability, inflation, taxes, philanthropy, and spending.

The tool that's most associated with the recent progress against malaria is the long-lasting bed net. Bed nets are a fantastic innovation. But we can do even better. We can invent new ways to control the mosquitoes that carry the malaria parasite.

People cannot become truly knowledgeable without being excellent readers.

AIDS we're - most of these diseases - we are down from the peak. We're down about 40 per cent from the peak and if we got the right vaccines, which are at the early stage of discovering, then the numbers would come down very dramatically. So that's why we talk about it as an emergency.

What's amazing is, if young people understood how doing well in school makes the rest of their life so much interesting, they would be more motivated. It's so far away in time that they can't appreciate what it means for their whole life.