Allen succumbed to non-Hodgkin's lymphoma. He died Monday afternoon at in his hometown of Seattle.
Allen, whose wealth was estimated North of $20 Billion, announced 2 weeks ago his cancer had returned after 9 years in remission.
Allen and Gates, both college dropouts, hatched the idea for Microsoft in Albuquerque. They designed software for the yet-to-explode person computer revolution.
The 2 men met when they were teenage students at Lakeside School in Seattle. They became fast friends and bonded over the love of computers. The two would go "dumpster diving" for computer program code. Allen, who dropped out of Washington State, convicted Gates to bail from Harvard.