Bill Gates (born October 28, 1955) is an American business magnate, philanthropist, investor, computer programmer, and inventor.In 1975, Gates co-founded Microsoft, the world’s largest PC software company, with Paul Allen. During his career at Microsoft, Gates held the positions of chairman, CEO and chief software architect, and was the largest individual shareholder until May 2014.Gates has authored and co-authored several books.He received Public Service Medal in 2013 for improving the lives of millions by applying science to some of the world's most difficult global health challenges.