Paul Gardner Allen was an American businessman, computer programmer, researcher, film producer, explorer, sports executive, investor, author, and philanthropist. He co-founded Microsoft Corporation with his childhood friend Bill Gates in 1975, which was followed by the microcomputer revolution of the 1970s and 1980s. Allen was ranked as the 44th-wealthiest person in the world by Forbes with an estimated net worth of $20.3 billion at the time of his death in October 2018.