Drow of the Underdark

Drow of the Underdark is the name of two supplemental rules books for the Dungeons & Dragons fantasy role-playing game, providing supplementary game rules focusing on drow culture, equipment and folklore for both players and Dungeon Masters.

Advanced Dungeons & Dragons 2nd edition
The Drow of the Underdark was written by Ed Greenwood for use with AD&D (2nd Ed.), and focuses primarily on the drow of the Forgotten Realms campaign setting. The book features cover art by Jeff Easley, and interior art by Tim Bradstreet and Rick Harris.

This book details the nature of dark elves, dark elven society, drow religion (including Eilistraee, Ghuanadar/The Elder Elemental God, Lolth, and Vhaeraun), the high history of the drow, drow spells, drow magical items, drow craftwork, drow languages, drow nomenclature, and dark elven runes. This book also details the Underdark of the Forgotten Realms, as well as several monsters of the Underdark (including the myrlochar and the yochlol).

Dungeons & Dragons 3rd edition
Drow of the Underdark was written for use with D&D (3rd ed.), and is not tied to any specific campaign setting. The book's format and contents are similar to that of Draconomicon, Libris Mortis, and Lords of Madness.

Although primarily intended for DM use, players can use information from the book to play as a drow character or half-drow character, as well as to fight against drow, or to adventure in the Underdark in general.

This book was designed by Ari Marmell, Anthony Pryor, Robert J. Schwalb, and Greg A. Vaughan. It features cover art by Francis Tsai, and interior art by Steve Ellis, Wayne England, Lars Grant-West, Tomás Giorello, Jackoilrain, William O'Connor, Richard Sardinha, Beth Trott, Francis Tsai, Franz Vohwinkel, Eva Widermann, and James Zhang.

Contents
The first chapter contains general information about drow and contains few rules other than drow racial traits. A guide to drow names and their meanings is also included.
 * "All About Drow"

This chapter contains new uses for various skills, new feats (including general, metamagic, ambush, divine, vile, and weapon style feats), alternate class features for many classes, and new spells and invocations (some of which require the user to be a drow).
 * "Drow Options"

New prestige classes in this chapter include Arachnomancer, Cavestalker, Demonbinder, Dread Fang of Lolth Eye of Lolth, Insidious Corrupter, and Kinslayer. Each prestige class also contains a sample NPC ready for quick use.
 * "Prestige Classes"

This chapter contains new mundane, alchemical, and magic items, along with poisons, magic-infused poisons, and artifacts
 * "Drow Equipment"

Numerous new monsters are presented in Drow of the Underdark, including the deep dragon, trolls, goblins, and draegloth. There are also numerous ready-to-use drow NPC statistics, both for "generic" NPCs (such as "drow slaver") and "specific" NPCs (like Xil'Etha Dhuvvaryl). Statistics for one monster, the vril, were accidentally left out of the book.
 * "New Monsters and NPCs"