AD&D Dungeon Master's Guide 1983/1999 (1e Revised)
The 1983 edition (Cover: a wizard opening 2 double doors). 9th printing¸ Aug 1987.
A compiled volume of information primarily used by Advanced Dungeons & Dragons game referees¸ including: Combat tables; monster lists and encounters; random dungeon generation; random wilderness terrain generation; suggestions of gamemastring; and more.