From the back of the adventure:
"ABYSS is second in a series of Pocket Adventures designed for solitaire play with the Tunnels & Trolls game system. To enter the Abyss, you'll need a few six-sided dice, paper, pencil, and the Tunnels & Trolls rulebook."
Arms Law (1st Edition), Cerberus: The Proxima Centauri Campaign, Dark Nebula, Hexagony, Junta, OK Corral,
Pegasus Reviews Games and Game Aids. Includes reviews of Abyss: Pocket Adventure #2 (Flying Buffalo), Spellbinder