The Four Lords of the Diamond 1-4.
1: Lilith: A Snake in the Grass. 2: Cerberus: A Wolf in the Fold. 3: Charon: A Dragon at the Gate. 4: Medusa: A Tiger by the Tail. Del Rey, New York 1981-83. 248 + 243 + 289 + 294 pages. Paperbacks; as new. 4 vols. [L]