A noted roleplaying game designer, he was one of the main designers on Dungeons & Dragons 3rd Edition. He also was one of the main developers on WizKids' game HeroClix.
Game design section of the biography from his personal website:
Monte Cook started working professionally in the game industry in 1988. In the employ of Iron Crown Enterprises, he worked with the Rolemaster and Champions games as an editor, developer, and designer. In 1994, Monte came to TSR, Inc., as a game designer and wrote for the Planescape and core D&D lines. When that company was purchased by Wizards of the Coast, he moved to the Seattle area and eventually became a senior game designer. At Wizards, he wrote the 3rd Edition Dungeon Master's Guide and served as codesigner of the new edition of the Dungeons & Dragons game. In 2001, he left Wizards to start his own design studio, Malhavoc Press, with his wife Sue. Although in his career he has worked on over 100 game titles, some of his other credits include Return to the Temple of Elemental Evil, The Book of Eldritch Might series, the d20 Call of Cthulhu Roleplaying Game, The Book of Vile Darkness, Monte Cook’s Arcana Evolved, Ptolus, Monte Cook's World of Darkness, and Dungeonaday.com. He was a longtime author of the Dungeoncraft column in Dungeon Magazine. In recent years, Monte has been recognized many times by game fans in the ENnies Awards, the Pen & Paper fan awards, the Nigel D. Findley Memorial Award, the Origins Awards, and more.
Featured in PROFILES Dragon #275 Sept 2000