Who co-founded Microsoft with Bill Gates?

Paul Gardner Allen (born January 21, 1953) is an American business magnate, investor and philanthropist. He is known for co-founding Microsoft alongside Bill Gates. As of August 2016, he was estimated to be the 40th richest person in the world, with an estimated net worth of $18.6 billion.

Allen is the founder and Chairman of Vulcan Inc., which manages his various business and philanthropic efforts. Allen also has a multibillion-dollar investment portfolio including technology and media companies, real estate holdings, and stakes in other companies. He owns two professional sports teams: the Seattle Seahawks of the National Football League and the Portland Trail Blazers of the National Basketball Association. He is also part-owner of the Seattle Sounders FC, which joined Major League Soccer in 2009.

In Albuquerque, New Mexico, Paul Allen with his friend Bill Gates, in 1975, began marketing a BASIC programming language interpreter. Allen came up with the original name of "Micro-Soft," as recounted in a 1995 Fortune magazine article.  He effectively left Microsoft in 1982 due to serious illness. He officially resigned from his position on the Microsoft board of directors in November 2000 but was asked to consult as a senior strategy advisor to the company's executives and still owns a reported 100 million shares.