William Henry "Bill" Gates III (born October 28, 1955) is an American business magnate, philanthropist, investor, computer programmer, and inventor. Gates is the former chief executive and chairman of Microsoft, the world's largest personal-computer software company, which he co-founded with Paul Allen.

He is consistently ranked in the Forbes list of the world's wealthiest people and was the wealthiest overall from 1995 to 2009—excluding 2008, when he was ranked third; in 2011 he was the wealthiest American and the world's second wealthiest person. According to the Bloomberg Billionaires List, Gates became the world's richest person again in 2013, a position that he last held on the list in 2007.As of April 2014, he is the richest.

During his career at Microsoft, Gates held the positions of CEO and chief software architect, and remains the largest individual shareholder, with 6.4 percent of the common stock. He has also authored and co-authored several books.

Gates is one of the best-known entrepreneurs of the personal computer revolution. Gates has been criticized for his business tactics, which have been considered anti-competitive, an opinion which has in some cases been upheld by judicial courts. In the later stages of his career, Gates has pursued a number of philanthropic endeavors, donating large amounts of money to various charitable organizations and scientific research programs through the Bill & Melinda Gates Foundation, established in 2000.