Bill Gates is one of the world’s richest men. Born in Seattle in the North West of the US in 1955, he began to show an interest in computers while at high school.
At 15, with his friend Paul Allen, he developed a computer programme which monitored road traffic patterns. They sold it for $20,000.
He went to Harvard University, initially planning a law career but he dropped out when he and Allen designed a programme for a new personal computer. It was 1975 and Microsoft was born.
Over the next 30 years, through a combination of technical innovation and aggressive business tactics, Gates’ firm became one of the best known brands in the world, a leader in the software business. It is estimated around 80 per cent of computers globally, use Microsoft Windows.
In 1986, Bill Gates started selling shares in his company, becoming an instant millionaire. He was just 31. The company quickly grew in value, and in just over a year, Gates was a billionaire.
He first met Microsoft executive, Melinda French in 1989. The pair married five years later - the same year the William H Gates Foundation was created, dedicated to supporting education.
In 2000, the couple combined several family charities and formed the Bill and Melinda Gates Foundation - starting with their own $28 billion contribution.
The enterprise took more of Bill Gates’ time so in 2006, he announced he was leaving his full time post at the Microsoft to devote himself to his charity work. His last full day was June 27th, 2008, but he remains chairman of the board.
The foundation concentrates its efforts in health, education and agriculture in both the developing and the developed world. Inevitably it draws criticism because of what it does and how it does it - yet each year it spends billions of dollars trying to live up to its mission to help all people lead healthy and productive lives.
Melinda Gates says that despite criticisms from the church, she still feels obligated to bring safe contraceptives to the developing world:" We shouldn't shy away, as a world, from doing things because we have made them difficult. Yes, contraceptives have had some sticky times in the past - absolutely - some not great things happened in Peru, our own country and in India and other places. But it means that we stepped back from it as a world and yet we are letting women die because they can't space their children."
On Talk to Al Jazeera, Bill and Melinda Gates respond to criticism and explain how they are trying to help people around the world.