 Gary Gygax (July 27 1938 - March 4 2008) is best known as being the co-creator of Dungeons and Dragons with Dave Arneson and as the co-founder of TSR Inc. along with Don Kaye.
As an avid Sci-Fi fan, coupled with a great imagination and an interrest in games, he started creating games at an early age, and started some gaming federations and conferences, most notable of which, probably is the Gen-Con.
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That may be the very reason, why he left TSR in the first place! But it really is spot on for D&D today. There's a 4th edition being playtested!