(CNN) -- Billionaire Bill Gates, until recently the richest man in the world, is about to pass another landmark.
The Microsoft co-founder, who more than anyone else is credited with introducing computers into homes and offices worldwide, clocks off from his final day at the office Friday after 33 years.
Gates, who Fortune magazine reports has an estimated net worth of $50 billion, formed what would eventually become Microsoft with Paul Allen, a friend from school, in New Mexico in 1975.
In 1981 the company launched MS-DOS, its first commercial software, which was licensed to IDM. It was followed four years later by Windows, which Gates allowed PC makers to pre-install on PCs, creating a ready-made market for the software. What do you think about Bill Gates? Share your comments here.
Other successes since have included further applications such as PowerPoint and Excel, the launch of the X-Box gaming system and the introduction of Internet Explorer.
On the downside there have been muted attempts to crack the music download market, the delayed launch of Windows Vista and the failed $45B-plus bid for Yahoo. The company's monopoly of the PC software market has also seen it fall foul of regulators both in the United States and in Europe. CNN's Maggie Lake looks at life after Bill Gates »
Tellingly, most of these failures have come in recent years, as Gates has gradually divested himself from day-to-day management of the company.
Within popular culture he has also come to symbolize the public perception of what a computer geek should be: bespectacled, skinny -- and very, very successful. To fans of the Apple Macintosh and other operating systems he has often been portrayed as a hate figure.
So what will a man who has earned around $1.5B for each of his years at Microsoft now do with his time?
As might be expected, Gates is still going to keep his hand in at the office -- he will, for example continue to chair board meetings and be on hand to offer advice to Steve Ballmer, who took over as CEO at Microsoft in 2000.
On a lighter note, a humorous video shown at a computer trade fair earlier this year showed rock star Bono rejecting Gates' pleas to join U2.
But much of Gates' free time will now be devoted to the Bill and Melinda Gates Foundation, which he and his wife founded in 1994 to "help reduce inequities in the United States and around the world," according to the organization's Web site.
The Seattle-based organization, the largest charity of its kind, has asset trust endowments of $37.3 billion and has committed to grants of $16.5 billion during its 14 years. In 2007 it made grants of just over $2B in 2007.
It has enjoyed an especial high profile for its work towards malaria control and eradication, for example, contributing $650M to Global Fund to Fight AIDS, Tuberculosis and Malaria.
In 2005 Time magazine named Bill and Melinda Gates as its Persons of the Year for their charitable work.
The foundation was bolstered still further in 2006 when businessman Warren Buffet -- who toppled Gates from his 13 years as the world's richest man -- endowed the foundation with more than $3 billion, as part of an ongoing plan to give away at 85 per cent of his fortune, currently estimated at $62 billion.
Bill Gates may be retiring from office life -- but he still has work to do.