Bernard Sampson, the narrator of this new Deighton spy-novel, is 40-ish, a soldier's son, Berlin-raised, non-Oxbridge--a sardonic veteran who has recently moved from the field to a desk, while his independently wealthy wife Fiona (mother of two) also works at Intelligence, fairly high up in Operations. Now, however, a series of odd, perhaps-connected developments is sending Bernie back into action. For one thing, Britain's longtime spy within East Germany's banking community--code-named ""Brahms Four""--is ready to defect, even though London wants him to stay put; and Bernie, whose life was once saved by Brahms Four, is the only agent who can handle face-to-face negotiations with this aging, restless spy. Furthermore, there's uneasiness within the ""Brahms Network"" of East Berlin spies--who are afraid of being exposed by some unnamed traitor . . . and afraid of giving up their shady financial (non-espionage) dealings. And most disturbing of all is the apparent treason of Intelligence desk-man Giles Trent--who certainly has been pasing data to a KGB agent (his spinster sister's lover). But isn't it strange how easily Trent's betrayal is unearthed, how obvious his Russian contacts have been? Could it be that the KGB is using the superficial Trent traitor-dom to cover up some more important, better-concealed traitor--someone closer to the top? So wonders Bernie, especially after Trent attempts suicide. And, teaming up with the one other top desk-man he trusts (but doesn't like), he tries to use Trent in a scheme to smoke out this high-level traitor. (The plan backfires, leading to Trent's murder by one of those fearful Brahms Network agents.) Finally, then, Bernie winds up sneaking into East Berlin for a meeting with Brahms Four as the plot-strands converge: Brahms Four knows the identity of the upper-echelon mole. . . and will trade that information for help in defecting. Only in these last chapters, with taut defection-action (featuring Brahms Four's plucky wife) and Bernie's growing fears about the mole's identity, does this thriller move into firm gear; earlier, the fragmented puzzles often read like le CarrÃ‰ manquÃ‰--without the tug or the texture. And Deighton's powerful central idea here--the husband/wife spy duo--isn't developed nearly as well as it could have been. Still, the neat character-sketches and London/Berlin atmosphere make it easy to keep reading right past the murky tangles; and once that Berlin-finale begins, Deighton's most serious spy tale in quite some time becomes compelling enough to make you forget most of those flaws, holes, and missed opportunities.