They have devoted almost all their time and energy to building up fortunes worth billions. And now they are going to give most of it away.
Warren Buffett: The World's third richest man is among those donating.In the biggest charity donation in history, 40 American billionaires have pledged to give at least half of their money to good causes.
Star Wars director George Lucas, New York Mayor Michael Bloomberg and Hilton hotels owner Barron Hilton are among those who will provide an estimated £250bn.
Others pledging fortunes include media mogul Ted Turner, fashion director Diane Von Furstenberg, David Rockefeller, the heir to the Rockefeller fortune, and construction billionaire Eli Broad.
The unprecedented commitment was brokered by Microsoft founder Bill Gates and investor Warren Buffett over a series of intimate dinners.
They set up The Giving Pledge, which asks billionaires to make a 'moral commitment' to give away at least 50% of their wealth to charity either during their lifetime or after their death. So far 40 have signed up.
It is up to the donors how the money will be allocated and which charities they want to give to.
Some of the billionaires had already pledged to give their wealth away but pulling all the names together makes it the single biggest commitment in history.
Mr Buffett, who previously pledged to give 99% of his wealth away, said: 'We've really just started but already we've had a terrific response. The Giving Pledge is about asking wealthy families to have important conversations about their wealth and how it will be used.
'We're delighted that so many people are doing just that - and that so many have decided to not only take this pledge but also to commit to sums far greater than the 50% minimum level.'
Dorcas Erskine, from charity Action-Aid, said the donors were 'leading by example'.
'It is not just about the money but also the experience and talent that these individuals bring to the table,' she said.
And Caroline Preston, from the New York-based Chronicle of Philanthropy, added: 'Bill Gates and Warren Buffett have been moved by their philanthropy and Gates is devoting all of his time towards it now.
'They have seen the positive impact it has been having and wanted others to be able to enjoy giving and also open others up to the idea of giving.
'I think this will have an impact in terms of expectations around what wealthy people give and it is possible we could see considerably more given.'
Meet the billionaires giving away £250bn?
George Lucas
Among the most successful film makers of all time, he has personal fortune of around £2bn. The Star Wars director, 66, has received a string of Academy Awards. Star Wars made over $400m on its first run alone.
Paul Allen
Unmarried with no children, Allen, 57 , has an £8.7bn fortune from cofounding Microsoft Resigned in 1983 over a cancer scare. He has already given away $1bn through foundations he has created.
Barron Hilton
One of the sons of Conrad Hilton, who started the Hilton hotel chain. The 82-year-old, full name William Barron Hilton I, is grandfather of socialite Paris.
He has a fortune estimated at £1.6bn and once announced he wanted to leave 9% of it to a charitable trust. According to US media reports, this was in part because he was embarrassed by Paris's antics. He has stepped aside from day-to-day running of the business but maintains a large interest in the empire.
Diane Von Furstenberg
The 63- year-old designer and her TV mogul husband Barry Diller, 68, have a fortune of more than £1bn. She is best known for her wrap dress whilst he approved shows like The Simpsons when working at Fox Television.
Bill Gates
Mr Gates, 54, was cofounder of Microsoft and he remains the biggest shareholder with a net worth of £33bn. With his wife Melinda, 54, he set up the Bill & Melinda Gates Foundation in 2000. It is one of the largest aid organisations in the world and has donated more than £17bn.
T. Boone Pickens
Four times married, the 82-year-old financier heads BP Capital Management and is worth about £ 2bn. In 2008 he launched a $58m ad campaign for his energy policy aimed at cutting America's addiction to oil.
Ted Turner
Founded the CNN news network and is worth about £1.1bn. Aged 71, he owns more land than any other American and has the largest herd of bison on the planet. He once gave a £700m gift to support UN causes.
David Rockefeller
Worth £2bn, he is patriarch of the Rockefeller family, one of America's best known dynasties. In 2008 Rockefeller gave $100m to Harvard. A key interest is Sailors for the Sea, which encourages mariners to preserve the oceans.
Warren Buffett
The third richest person in the world, Mr Buffett slipped down the rankings as he gave money away. He made his £30bn fortune through investments with his company Berkshire Hathaway. In 2006 the 79-year-old vowed to donate 99% of his wealth to charity.
Michael Bloomberg
Financial news tycoon with a £12bn fortune who is serving his third term as mayor of New York. The 68-year-old once said: 'I have always said the best financial planning ends with bouncing the cheque to the undertaker.'