TSR Code:

'The place has many names: the Underdark, Deepearth, the Realms Below, the Night Below, the Lightless Lands.  This vast world beneath the surface is home to fabled races such as beholders, cloakers, drow, illithids and ixzan.  Menzoberranzan, the dreaded City of Spiders, is only one of the hidden cities of the Underdark. This 128-page book, compiled by the Underdark's most famous son, Drizzt Do'Urden, lays bare the bizarre societies that lurk in the Realms Below. It includes an overview of the major races of the Underdark, an Underdark survival guide, and details and maps of more than a dozen cities.  Discover a drow city constructed entirely  of calcified spider silk, a nigh-immortal dwarven king trapped in a stone form, and a storehouse of knowledge that rivals Candlekeep.  Learn the particulars of the alliance between Manshoon and the beholders of Anaurian Hive, the ambitions of the true master of Firedrake Bay, and an explanation of the enduring strength of the beholder cults along the Lake of Steam.
With Drizzt Do'Udren as your guide, a whole new world opens up beneath your feet'.