If they liked it once, they'll love it twice. That's the wise rationale behind Follett's new WW II thriller, which recycles the same basic scenario--now in 1942 Cairo instead of 1944 England--that made Eye of the Needle such a winner. Again the central figure is a Nazi spy with secrets that could change history: Arab-German Achmed, a.k.a. Alex Wolff, is sent to his native Cairo (in the splendid opening, he walks there from Libya) to gather secrets from the British and broadcast them to Rommel in the desert, using pages of du Maurier's Rebecca for a code. And, after a few bumbles (he steals a briefcase full of army menus), Achmed/Alex is a success, thanks to his moll--bisexual, masochistic, Anglo-loathing belly-dancer Sonja; together they lure a wimpy British major into feverish liaisons with Sonja on her houseboat. . . while Alex steals secret papers from his briefcase. So Alex does broadcast to Rommel, who's thus able to win at Tobruk and Mersa Matruh, closing in on Cairo. But someone's after Alex, of course. William Vandam of Army Intelligence, an introverted widower with small son, has picked up the elusive spy's trail--a murder, forged currency--and almost captures him at a nightclub (Alex escapes, knifing Vandam in the face). Vandam's primary plan, however, involves Elene Fontana, an Egyptian-Jewish courtesan (eager for a new life in Palestine) who agrees to pose as a clerk at Alex's favorite grocery. And sure enough, just after getting the secrets of the El Alamein line from the Major (who is graphically drowned), Alex invites Elene to the houseboat for menage a trois with Sonja. From there on, it's a pure (and pretty corny) Buchanesque chase: Vandam follows them to the boat; Alex grabs Elene and Vandam's little son, racing to where his spare radio is hidden; Vandam (now in love with Elene, and vice versa) pursues, determined to rescue his loved ones and to use Alex's radio to broadcast fake El Alamein info to Rommel. . . . The plotting's fine--except for a half-baked subplot about pro-Nazi nationalists, like young Sadat--and the characterization's serviceable, though lacking the gripping ambiguity of Needle's sympathetic villain. What's special here, however, is Follett's Ambler-ish feel for spying's unglamorous side, his subtle threading-through of the Rebecca motif (Vandam's late wife), his totally lean yet atmospheric narration. Top-notch entertainment--shrewdly paced, cannily crafted.