Del Rey Gold Seal, New York, 1981, 1^st trade ed/pr.  ISBN 0-345-29829-2.  Trade soft cover, 201 pages.  Wraps show some edge and cover wear, sun fading, small corner bends and scrapes; binding sound.  Some age spots on outer page block and stain at top edge near spine.  Book interior clean and unmarked; straightened corner bends.  ‘Four men were on board the atomic subtug Fenian Ram S1881, on a mission to steal vitally needed oil from underwater deposits in enemy territory – a mission from which none of the last twenty tugs had returned.  Four men.  Fighting a war a mile and a half under the ocean, isolated by the unrelenting pressure of the water and by their own hellish fears.  Four men.  They knew everything they had to know about one another – except which one of them was the saboteur who could destroy them all!’ (from rear wrap)