The Thieves' World boxed set is a role-playing game setting, featuring contributions from noted Thieves World novelists such as Poul Anderson and Robert Asprin.
The boxed set includes the following items:
The Player's Guide to Sanctuary (two copies)
The Game Master's Guide to Sanctuary
Personalities of Sanctuary
fold-out brown-and-white maps of Sanctuary, the Maze, and the Maze Underground
The boxed set is mostly a setting guide, but it also contains sections with statistics and rules for a wide number of different role-playing game systems popular at the time of publication:
Advanced Dungeons & Dragons
Adventures in Fantasy
Chivalry & Sorcery
DragonQuest
The Fantasy Trip
RuneQuest
Traveller
Tunnels & Trolls.