Blackford Oates, the Yalie CIA smoothie who was busy bedding and Saving the Queen in 1976, returns--in a slightly less giddy but still light, terribly bright piece of tongue-in-chic 1950s intrigue. With his engineering degree as a cover, "Black" is sent to oversee the Marshall Plan renovation of a war-ravaged 13th century German chapel--which just happens to be the family chapel of Count Axel Wintergrin, the charismatic anti-Communist leader of a movement to expel the Soviets and reunite West and East Germany. If Axel beats Adenauer in the upcoming election, he's likely to bait Stalin into a WW III-ish confrontation, so Washington and Moscow both want to make sure that Axel loses. . . or dies. Trouble is, Black comes to admire Axel ("the great hope for the West") and is mighty torn when he loses the draw--he and a brilliant KGB Mata Hari actually cut the cards--and must therefore be the one to "eliminate" Axel (via electrocution, as Axel examines stained glass for the chapel at the chromoscope). Suave Mr. Buckley fumbles now and then, waxing overcute (a Soviet lackey is called "Stepovich Fechitov") or wearing his conservative heart on his perfectly tailored sleeve. But his clean, unpadded plotting and his literate relaxation should prove a relief from the tortured efforts of the Le Carré imitators, and anyone who can make conferences between Allen Dulles and Dean Acheson sound like vaudeville routines deserves the audience he's bound to get.