From the back of the book:
Ugly, brutish, malevolent and in service to dark powers: the uz of Glorantha have a bad reputation which is all too well deserved. Trolls: A Guide to the Uz presents everything Games Masters need to present these brutes as detailed enemies in Glorantha campaigns, as well as including the necessary lore for players to portray uz characterS themselues, seeing how it feels to play the 'other side' of things.
Included are expanded details on uz culture and physiology, Regional differences between the trolls, as well as new Rules for troll magic. The dark magic of troll cults, that revere many of the most sinister deities ever to walk the face of the world, are also described in Trolls: A Guide to the Uz.
As either allies or enemies the uz provide players and Games Masters alike with a race rich in history and legends, a species just and fair one moment and savagely bloodthirsty the next.
Welcome to the world of the uz!