From the back cover:
The Thieves' World series began in 1979 to instant acclaim. Not long after, Chaosium published a boxed Thieves' World roleplaying supplement, which gathered awards and more acclaim. Since the first book hit the newstands, more than 2200 paperback pages and eight additional Thieves' World volumes have been printed - a phenomenon others imitate but cannot duplicate.
Sanctuary, the town too mean to die, has changed a little from the time it first saw print, but many new characters now stride the city's streets, pillage the foolish in its alleys, and connive in its back rooms. Lalo, Ishcade, Roxanne, Niko, Mradhon Vis, The Beysa, Chenaya, Zip, and many more have come to life, and are now included in the Companion's full character stats for the RQ3 and MERP systems.
New essays consider Rankan, Ilsigi, Beysib, and Outsider deities in the light of further tales of Sanctuary, that place which is the funnel of the gods and the eye of the Rankan hurricane. The excellent encounter tables from the Thieves' World box have been revised to reflect later events and personalities, and are presented her in full. There are also floor-by-floor isometrics of the Great Dungeon. Though adjacent to Kitty-Cat's palace, nobody seems to go there. Now you can study its defenses and understand why.
Alone or with the Thieves' World box, the Companion rekindles the fabulous world of Sanctuary - Thieves' World.