Its licenses include products based on the science fiction properties Traveller, Judge Dredd, and Paranoia, as well as fantasy titles.
[1][2] Sprange initially wanted to publish a miniatures game, but he ultimately went with the less expensive alternative of using Wizards of the Coast's d20 System license.
The first release, the Slayer's Guides, concentrated on different monster types for the d20 system, while the subsequent Quintessential books, detailed specific character classes.
Further acquisitions followed the same year, including the rights to a roleplaying game based on Conan the Barbarian (released in 2004), the roleplaying game Paranoia and a joint venture with d20 System portal EN World, the EN World Gamer quarterly magazine.
In May 2011, Sprange announced that Mongoose Publishing and Issaries Inc. had parted ways, meaning that Mongoose would cease publication of RuneQuest, though they retain the copyrights to the revised RuneQuest II core rule system, which was re-released under the title Legend.