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.

It's a nice reader, but there's nothing on the iPad I look at and say, 'Oh, I wish Microsoft had done it.'

The potential financial reward for building the 'next Windows' is so great that there will never be a shortage of new technologies seeking to challenge it.

The computer was born to solve problems that did not exist before.

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.

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.

My broad sense of this is that authors like Smil really paint the clear picture, and once you see that, it's kind of Oh, of course. That's such a primal thing to all these physical services that we take for granted.