Judges Guild was founded on July 4, 1976, utilizing concepts developed by co-founder Bob Bledsaw, in his home Dungeons & Dragons (D&D) campaign.
Bledsaw, along with partner Bill Owen, travelled to Lake Geneva, Wisconsin to visit the headquarters of Tactical Studies Rules (TSR), publishers of Dungeons & Dragons, on July 17, 1976.
The company rapidly gained popularity amongst D&D fans for their prolific product line and then-unprecedented detail, at a time when such sources were rare.
Its production values were stagnant as the roleplaying games industry moved to professional typesetting, full color art, and slick and hardcovered material, elements Judges Guild was slow to adopt.
The company also produced licensed products for Advanced Dungeons & Dragons, Traveller, Chivalry & Sorcery, DragonQuest, Empire of the Petal Throne, Tunnels and Trolls, RuneQuest, Superhero 2044 and Villains and Vigilantes.
Judges Guild returned in 1999, selling revised copies of the City State of the Invincible Overlord, a reintroduction of Pegasus magazine that lasted two issues (#14 & #15), the Revised Treasury of Archaic Names, and an edited version of Dark Tower, in addition to classic original products; the company also produced products for the d20 System.
In 2002, Necromancer Games, under license and in cooperation with Bledsaw and other original Judges Guild writers published revised editions of the City State of the Invincible Overlord, the Player's Guide to the Wilderlands, the Wilderlands of High Fantasy compilation boxed set and a revised edition of Caverns of Thracia, all for use with the d20 System.