Sherry offered me a list of research options: the one project that intrigued me the most consisted of finding out the environmental fate of certain very inert industrial chemicals – the chlorofluorocarbons (CFCs) – which had been accumulating in the atmosphere and which at that time were thought to have no significant effects on the environment. This project offered me the opportunity to learn a new field – atmospheric chemistry – about which I knew very little; trying to solve a challenging problem appeared to be an excellent way to plunge into a new research area.

When I decided to sell my company, I already had enough. I live simply. I don’t own a house, a car, or even a TV. The less I own, the happier I am. The lack of stuff gives me the priceless freedom to live anywhere anytime. So I didn’t need or even want the money from the sale of the company. I just wanted to make sure I had enough for a simple comfortable life. The rest should go to music education, since that’s what made such a difference in my life.

We need to have mentors. I think I've always been pretty shameless about seeking out people much smarter and much more experienced than me from the very beginning. Michael Seibel and other people. And the more successful I got, the more leaders I started seeking out, whether it was investors, or Sheryl Sandberg at Facebook, or I got the opportunity to spend time with Warren Buffett and he became a close mentor of mine.

The friends with whom I sat on graduation day have been my friends for life. They are my children’s godparents, the people to whom I’ve been able to turn in times of trouble, people who have been kind enough not to sue me when I took their names for Death Eaters.

One of my editors once said to me, “If you get invited to the White House, take your notebook with you,” and he meant it. It’s something one has to always remember because when you stray off the path, you do a disservice to the American public.