Enemy in the Dark (Perry Rhodan #85) By Kurt Mahr Books / Paperback ISBN: B000H6MDR0 / Publisher: Ace, January 1975 Price $6.81 Free Shipping Send to a friend Collectible - Very Good New York: Ace Books, 1975. Book 85. 16mo mass market paperback. Very Good book. Inquire if you need further information. $6.81 1 in Stock at Warehouse Quantity Add Free Shipping to continental U.S. OR $1.00 per item discount if shipped to store.