This incredible book (and several minor booklets), create what just may be the single largest Mega-Dungeon ever! At a retail price of $100.00 it's not cheap, but the sheer volume of material is worth every penny.
Clocking in at 672 pages (counting a few advertisements), its very hard to believe that this entire series was based on three ordinary modules by Necromancer Games - R1 = "The Dungeon of Graves - Upper Levels" at 48 pages, R2 = "The Dungeon of Graves - Middle Levels" at 64 pages, and R3 = "The Dungeon of Graves - Lower Levels" at 112 pages.
15 main levels to Rappan Athuk, and a number of side quests and supplements, which were released on their own. I'll mention those in separate reviews. The layout and design of Rappan Athuk is very good, and the table of contents in the front is a big help. There is no index. To be fair, at this size of scope, I did not expect color art.
The wilderness areas outside the dungeon should only be attempted by a party of at least an average of level 4 or better. The chart about levels of Rappan Athuk is a big convenience. A lower level party just traveling through the area on the way to something else should simply mark the danger(s) on their overland maps and come back prepared for anything.
The outer area of the main dungeon consists of three areas to start in - 1st Level 0A = "The Cavern of the Kraken" or Level 0B = "The Cloister of the Frog God", or Level 0C = "Zelkor's Ferry". A more sadistic GM would use either level 0A or 0B. Even on Level One of Rappan Athuk, there are three sub-quests. There's almost always a sub-quest or two in every level, except for Level 15 - "The Chapel". There are 53 quests and sub-quests, and seven appendixes.
I won't spoil the fun, but any Game Master worth his salt could possibly use this mega-dungeon from the PC's starting at level one and then all the way to level 20. A few new monsters, a couple new classes, some new magic items, the Gods and Demons of Stoneheart Valley, some very good pre-generated characters, a few battle maps, and the final revelations.
Because other products by Frog God Games are mentioned (such as "Stoneheart Valley" above) this super dungeon gets even bigger! With the additions of the remaining Frog God products, I suspect (because I'm still missing one or two) that there are =well= over a thousand pages of material! I can't recommend this any higher! With the addition of the supplementary material, I don't have to move my PC's at all unless they want to leave the area! This has got to have one of my very highest recommendations!