Frank Mentzer

Jacob Franklin Mentzer III is an American fantasy author and game designer who worked on early materials for the Dungeons & Dragons (D&D) fantasy role-playing game. He was an employee of TSR, Inc. from 1980 to 1986, spending part of that time as creative advisor to the chairman of the board, Gary Gygax. He also founded the Role-Playing Games Association (RPGA) during his time with TSR.