Avon, New York, 1988, 1^st pr thus.  ISBN 0-380-89637-0.  MMPB, 217 pages.  Very good; some edge and cover wear, creased spine, binding sound with a slight lean.  Interior clean and unmarked with lightly tanned pages.  ‘… Merlin, son of Prince Corwin, pursues his noble destiny against a shifting panorama of shadow worlds and deadly intrigue, powerful computers and magic gone out of control.  A violent vendetta … renegade sorcery … and whirlwind adventure lead Merlin to a monumental confrontation at the Keep of the Four Worlds, where astonishing secrets and mysterious identities will at last be revealed!’ (from rear wrap)