The first thing about Ruins of Undermountain (1991) I want to talk about is the cover art, which is by Brom, if you can believe it (it just doesn’t look Brom-y to me). This is probably my favorite artistic expression of the concept of “A Dungeon” and I find it extremely evocative. It makes me think of Zork, and also Christopher Manson’s Maze.  

Anyway. Undermountain is the vast dungeon beneath the city of Waterdeep, once a dwarven kingdom, now the playground of the mad mage, Halaster Blackcloak. The box set is a mega-dungeon (sort of), detailing (sort of) the first three levels of the place (in four giant poster maps, which are pretty but unweildy) that has taken on a bit of a legendary rep thanks to it being a key part of Forgotten Realms creator Ed Greenwood’s own campaign. With Waterdeep above, the Underdark below, endless planar gates throughout the complex and an owner who likes to change things around at will, Undermountain is intended to be a place where anything can happen.

Much of the box is dedicated to running down the history of the place, how it works in broad terms and the personalities of the NPCs, while leaving most of the actual dungeon details blank for the DM to fill in. There are a bunch of lovely random tables to help, which are swell, but you are either going to love this or hate it.

My take: for all the possibility Undermountain presents, it feels oddly static. Because it is constantly changing, players never leave their mark on the place. And, because so much of the box is given over to justifying the ways it breaks certain rules for the players (no travel magic, no gates, etcs) while not applying the same to NPCs and monsters, I feel that Undermountain would get real frustrating real fast for my players. With so much of the work left to the DM, Undermountain seems ripe for strip mining rather than playing. YMMV, of course.