Bill Gates: Do I fly first-class? No, I have my own plane. . .
The Microsoft mogul opens up to Mary Riddell about his charity work, acting in 'The Social Network' -- and his life of luxury
Bill Gates is an economical man. He does not waste money, although he is as rich as Croesus, and nor does he waste words. After a muttered hello, he sits in silence, waiting for the questioning to begin.
Mr Gates, at 54, is the kind of prophet whose spectacles and nondescript suit brand him an off-the-peg geek.
Does he mind that label? "Well, when geek means that you're willing to study things, and if you think science and engineering matter, then I plead guilty, gladly. Also, I kinda hang around with people who are like that.
"In our work, numbers give you the sense of scale, and then you meet the individual mothers and children and farmers. So yes, it's good. If your culture doesn't like geeks, you are in real trouble."
Most people admire Bill Gates. A Harvard drop-out, he founded the Microsoft empire before setting up the largest charitable foundation on earth. In addition to the £21bn held in The Gates Foundation, which he runs with his wife, Melinda, he has persuaded the affluent of America, Warren Buffett and Oprah Winfrey included, to give a slice of their fortunes to the world's poorest.
Already the foundation's endowment is greater than the GDP of half of all nations, and it may expand to $100bn.
So when Mr Gates visited London last week to give a public lecture at the Science Museum (he also met UK PM David Cameron in Downing St), the great and the good queued to hear him expound a message that he calls 'Living Proof'. Aid is working, he says, and his crusade to stamp out polio, attack malaria and find a vaccine for AIDS provides the proof. He alone can claim to have saved five million lives.
"Lifting up very poor societies can be justified on two grounds. The strongest is on the moral grounds that lives do have equal value."
Mr Gates's own career started relatively modestly. The child of a lawyer father and a philanthropic mother, he left Harvard to pursue his "sense of vision and risk-taking. I knew I wanted a personal computer for myself, and I knew what it needed to have".
He has never, he says, longed for endless new cars or any of the trappings of materialism.
"Well, I buy a lot of books."
There is one other luxury. "I travel." First-class, I ask, and then realise this is like asking if the Pope takes the bus.
"No, even better than that. I happen to have a plane. But beyond that extravagance, how much food can you eat, how many clothes can you wear?
"My kids go to a nice school, and I have an exercise machine that I should use more. Beyond a reasonably limited amount, it all goes to charity, but in no sense have I denied myself anything I wanted.
"I just didn't happen to want to build a pyramid and own many things. The really worthy people give up something, or take less of a vacation. I haven't made any sacrifice, so their philanthropy is more impressive."
He would have hated, he says, to grow up expecting to inherit a lot of money.
"People would have treated me in a strange way. It would have been very weird and demotivating."
He has already said his own children, aged 14, 11 and 8, will be left "some money but not a meaningful percentage".
How much, exactly?
"We're still figuring it out. But well over 95% of the fortune goes to the foundation, so it will be quite a modest amount."
He is also an unequivocal fan of the inheritance tax.
"Me and my dad are the biggest promoters of an estate tax in the US. It's not a popular position."
Now he says that he expects his children to fend for themselves during his lifetime.
"Once they graduate from college, then they're largely on their own. They're very lucky in that they'll get a great education and, compared to most children on the planet, they have a very good deal."
For all his good deeds, there is a suspicion of philanthro-capitalism by those who argue that the wealthiest, like him, have acquired unreasonable riches.
"People are welcome to any view they want. Some people, through luck and skill, end up with a lot of assets. If you're good at kicking a ball, writing software, investing in stocks, it pays extremely well. Capitalism has worked very well. Anyone who wants to move to North Korea is welcome."
Even so, he is a frugal capitalist. "I love sitting with my son and watching videos about things he's curious about. What are steel alloys? What is fertiliser?"
His marriage to Melinda, who used to work for him, has been an unqualified success. "I'm very lucky in everything, particularly in that." Charity work, he says, has given him more freedom. "I play tennis, I play bridge, we take vacations, we ski -- we get to do a lot of fun things."
While fun might not be his top priority, he is an A-list celebrity with a cameo role in The Social Network, the hit film about the foundation of Facebook. Although rumours that he played himself in the movie are false, he concedes it is "correct that Mark (Zuckerberg, founder of Facebook) went to a lecture I gave at Harvard about starting Microsoft."
Which parts of the film aren't correct? "I'm not going through all that. Mark is a great guy, and this film doesn't really give you a sense of Mark."
Mr Gates, far from being a pious plutocrat, also qualifies as a bona fides great guy.