If Moscow Interlude became a film, it might do for the Soviet capital what The Third Man did for Vienna and its background has much of the same secretive, sinister allure. Unfortunately, former diplomat Charles Thayer (Bears in the Caviar, etc.) is not Greene-his characters are more commonplace and his dialogue is sometimes forced. Still the novel is interesting and it is the intrigues and iniquities, the atmospheric touches, the Embassy parties and Gorky Street cafes which make it so. Thayer has spent eight years in the shadow of the Kremlin and one can sense the keen edge of experience in spite of the papier mache plot. As for that, it concerns the beautiful Elena returning with her American foreign service husband Sam to the homeland she fled during the terror of the '30's. That ""thaw"" has set in--there are hams in the shop windows and Teddy boy types on the street; musicians can peter about with the twelve tone and a non-Party member loafer is the hero of a play. Elena falls in love with a young intern and finds her long lost brother; the latter turns out to be a strong-armer of the dreaded police and the affair with the lover endangers her husband and compromises her own loyalty. Round and round go international relations, forged passports, hidden recorders, militiamen, truth drugs, liquidations, Intourist phone bugging and the old motto-one life, one kopeck. Moscow's the real draw here in a book which is notably a fetching guide to a fascinating city.