Glorantha is one of the oldest settings known to tabletop gaming, having first come to life in the board game White Bear and Red Moon published in 1975 by The Chaosium. It has since been used as the default setting for nearly every edition of the Runequest tabletop RPG, a video game called King of Dragon Pass.
Originally called HeroWars, a rule system created by Glorantha creator Greg Stafford and game designer Robin Laws to better simulate Stafford's vision of the world of Glorantha. With a second, revised edition of these rules the game's name was changed to HeroQuest (after a board game of the same name went out of print and the publisher let its rights to the name drop). HeroQuest Glorantha is a standalone game, based on the second edition of the HeroQuest rules, that has everything that you need to play a HeroQuest game set in Glorantha.
HeroQuest uses a set of simplified rules that are geared more towards a narrativist goal of storytelling instead of a simulation of physics of the game's world. This allows for an exploration of the myths and stories of Glorantha by your characters, and through embarking on mythic "heroquests" within the game, your characters can become a part of the myths of the world as well. HeroQuest Glorantha is currently available in preorder from Moon Design in print, with a PDF option that is available immediately for purchasers.
HeroQuest is also available in a settingless version from Moon Design as well.
Christopher Helton is a blogger, podcaster and tabletop RPG publisher who talks about games and other forms of geekery at the long-running Dorkland! blog. He is also the co-publisher at the ENnie Award winning Battlefield Press, Inc. You can find him on Twitter at @dorkland and on G+ at https://plus.google.com/+ChristopherHelton/ where he will talk your ear off about gaming and comics.