From publisher blurb: The third in a series of playing aids based on the world Dyon. It is one of three dungeond used at ProCon I during the summer of 1980. Over a year in the making this dungeon proved a challenge to all who entered.It was used in the 1st-3rd and 4-6th level categories. The other dungeon used at this level was Notnaidag Robber Headquarters also one of my designs.I hope that you who are playing this dungeon will have as much fun as the people at ProCon and the Stygian Wargaming club that play-tested it. Author John C. Clegg Tombs of Valla, 1st Printing 1980