How does a man find his calling?
By trying different things and being ready to change. In my case, what I now see as my calling – my ability to synthesize information into books about history and human society – I didn't find until I was in my fifties. Before that I was a specialist in gallbladders at UCLA medical school. At 24, gallbladders seemed very important to me. They don't seem so important now.

Have you ever cheated death?
I was on an island in Indonesia, and I needed to get to the mainland. There were canoes with big outboard motors for hire, piloted by crews of brash, cocky young men. I made the mistake of getting into one with about five other passengers. The pilot roared off, gunning the engine through the waves. Soon the canoe began taking on water, and eventually it overturned. This was about two hours before sunset and we were miles offshore. There were only three life preservers, and the crew took them. If we had not been spotted before nightfall, we would not have survived. Fortunately, two little sailing canoes appeared from nowhere and rescued us.

How should a man face his fears?
I just anesthetize my feelings and do what has to be done. I've been in lots of hopeless-looking situations before, and I'm still alive. So the expectation is, no matter how hopeless it looks, I will live, so let's just get through it.

What adventure most changed your life?
I was in New Guinea studying birds, and I found a campsite beneath a tall tree. The New Guineans with me grew anxious and said, "This tree is dead. It might fall down." Nothing happened, and I thought they were being paranoid. But then I thought, they sleep in the jungle 100 nights a year. A tree might actually fall over and kill them. That incident changed me. It affected how I drive, how I walk on slippery sidewalks. Even something low-risk can catch up with you. It's the odds times the number of repetitions.

How should a man handle regret?
Try not to get caught up in regret in the first place. Most people get paralyzed by regret.

What book should every man read?
The book that most influenced my life was 'Walden,' by Thoreau. The message of Walden is not to go live on some remote pond – it's not even about going off by yourself. The main message is to figure out what is important in life and do it.

What one thing should every man know about money?
Make sure you have enough to fulfill your needs but don't put too much effort into getting it. And don't acquire more money than is necessary for your needs.

Do you have a favorite drink?
The greatest wine in the world, in my opinion, is a German white called Scharzhofberger. It's very light and acidic, only about eight percent alcohol, and it has what's called an earthy taste. It's also bubbly, like a miniature champagne.

How should a man handle getting old?
I'm 74. The likelihood statistically is that I will live to about 90. So I think about what I want to do with the next 16 years. I want to write another book. I want to spend time with my wife and children. And I want to spend more time listening to music that I love and reading books that I love.

What advice would you give your younger self?
Remember that you're probably going to live for another 50 years. Don't get locked up
in the immediate goals of what you're going to do and where you're going to move and how much you're going to earn.

Is there a key to staying young?
There are two. One is to work out several times a week. The other is to marry a younger woman.