Bill Gates, the chairman of Microsoft and for years the world's wealthiest man, is a full-time philanthropist. In 2008, Mr. Gates walked away from his day-to-day duties at Microsoft and shifted his energies to the Bill and Melinda Gates Foundation, whose goals are curing the world's fatal diseases and improving American education.
Mr. Gates, a Harvard dropout, was an animating force behind the personal computer revolution, helping to build a huge global industry and engineer blockbuster products like Windows and Office, used every day in offices and homes around the world.
When Mr. Gates spoke about his philanthropy to the Harvard graduating class of 2007, his speech echoed the language of Microsoft, focusing on finding the ''ideal technology'' with the right ''application'' to tackle problems like malaria. Yet experience has taught Mr. Gates and others that, compared with government budgets, even their vast fortunes are a drop in the bucket.
When he began his philanthropic life more than a decade ago, Mr. Gates was driven by his conviction that providing incentives for pharmaceutical companies to develop drugs for the diseases of the poor world would be enough to avoid millions of deaths. He did not give much thought to the practicalities of getting health care systems in poor countries to deliver the drugs and educate the needy to use them. Likewise, he assumed that if his giving succeeded in developing a better sort of school for deprived urban areas in America, then that model would be widely adopted without his having to think about the political economy of education reform.
That was before he went full time at the helm of his foundation, which grew sharply in 2006 when Warren E. Buffett announced that he would contribute $31 billion, most of his immense fortune. Since then, Mr. Gates has devoted a growing amount of his time and his public speaking to