On Monday, December 19, 1955, two dogs and ninety-four Americans, all members of the U. S. production, Porgy and Bess, left East Berlin to travel by train to Leningrad, U.S.S.R., where the opera was to have its Russian premiere. This was the first American theatrical company ever to invade the Soviet Union, an event destined to receive world-wide attention. Mr. Capote, whose narrative covers the eight-day period between the Berlin departure and Leningrad premiere, accompanied the train for the purpose of recording the intimate aspects of a cultural exchange. Here it is: a swift, startling, factual account that reads like a novel.