Gates, who dropped out of Harvard in his junior year before co-founding Microsoft Corp. and going on to become the world's richest person, stopped off at his former stomping grounds to collect an honorary law degree.

Former Harvard Univeristy president Lawrence Summers (L) and Chairman of Microsoft Corporation Bill Gates talk during the 356th Commencement Exercises at Harvard University in Cambridge, Massachusetts June 7, 2007. Both Summers and Gates received honorary Doctor of Laws degrees. [REUTERS]

"We recognize the most illustrious member of the Harvard College class of 1977 never to have graduated from Harvard," said Harvard University Provost Steven Hyman.

"While his classmates, including his friend Steve Ballmer, were busy cramming for midterms, he was planning for a revolution, the rise of the personal computer," Hyman said. "It seems high time that his alma mater hand over the diploma."

Ballmer is now Microsoft's chief executive officer.

During Hyman's comments, Gates, 51, smiled and nodded to the applauding graduates. He was scheduled to address them later on Thursday afternoon.

The lack of a degree didn't slow Gates' rise to the top echelons of business.

In 1980, Gates and his colleagues at Microsoft were canny enough to negotiate an agreement with International Business Machines Corp. that gave the start-up software company the right to license its operating system for a new generation of personal computers to other manufacturers.

That arrangement ultimately turned the computer business on its ear, shifting power from hardware manufacturers to software programmers. Today, hundreds of companies manufacture hundreds of thousands of brand-name personal computers each year, but more than 90 percent of those machines use Microsoft's Windows operating system.

PHILANTHROPIC WORK

At Harvard, Gates lived down the hall from Ballmer, who stayed on to graduate after Gates dropped out to focus his energies on Microsoft, which he founded in 1975 with childhood friend Paul Allen. Ballmer joined Microsoft in 1980.

Microsoft went public in 1986 and by the next year the company's soaring share prices had made then-31-year-old Gates the world's youngest self-made billionaire.

Last year, Gates said he would step down from his day-to-day management role at Microsoft in 2008 to focus on philanthropic work.

The Bill and Melinda Gates Foundation, founded in 2000, supports projects to improve health, reduce poverty and increase public access to technology.

Gates' commitment to charity caught the attention of famed investor Warren Buffett, the world's second richest man. Last year, the chief executive of Berkshire Hathaway Inc., pledged the bulk of his fortune to the Gates Foundation.

That $30.7 billion donation, to be paid out in stages on the condition that the money be given away in the year it is donated, roughly doubled the size of the Gates Foundation.

Harvard also awarded honorary degrees to former National Basketball Association great Bill Russell and former treasury secretary Lawrence Summers, a former president of Harvard who was forced out after making controversial comments about women in academia that ignited a firestorm among the faculty.