From the Publisher's Website:
The Dungeon Alphabet — An A-to-Z Reference for Classic Dungeon Design
Designing dungeons is as easy as A, B, C! The Dungeon Alphabet compiles twenty-six classic dungeon design elements in one place to assist the game master in creating subterranean challenges. A is for Altar, B is for Books, and C is for Caves: the Dungeon Alphabet has advice, hints, and randomized tables that bring new life to your adventures. Suitable for any rules system, the entries are accompanied by outstanding art from classic fantasy illustrators, with a foreword by noted game designer Zeb Cook.
For the expanded edition see The Dungeon Alphabet: Expanded Third Printing.