Gen Con IX Dungeons (4th printing), softback adventure for Original D&D
“The Original Gen Con IX Dungeons Collectors Edition
Preliminary & Final Rounds of the Dungeons & Dragons Tournament”
These two dungeons were the official D&D tournament adventure at Gen Con IX way back in 1976, subsequently published commercially by Judges Guild in 1978. This is one of the JG 1978 printings.
The outer (monochrome) cover is badly stained and is loose, but the interior pages are largely clean.