As you get older three things happen. The first is your memory goes, and I can't remember the other two.

Don't get me wrong: I'm overjoyed with my career to date. But perhaps I could have done more. Mostly, I just did whatever the directors told me to do.

My only phobia is untidiness. My hair has to be neatly kept; my shoes are always clean. Everything has to be in a straight line, in its place.

I must admit I like to muck around a bit; I always have.

I first had the idea of writing a popular book about the universe in 1982. My intention was partly to earn money to pay my daughter's school fees.

This could be done in part, because the equipment was very inexpensive. Not much money was involved in tooling so that basic changes of that type could be accomplished.

There are a lot of jobs in the financial industry that do need a math major.

Money is not the ultimate point, but it remains the actual measure of success.