Not for the uninitiated, this history of baseball's fiercest feud is dense with details of management, and managers, price figures for players and sales of players of many years past, and much questionable desiderata. Questionable for its interest. Author Allen, whose office is at the Hall of Fame in Cooperstown, N.Y., is baseball's official historian and his love of baseball lore that time has otherwise spurned is perhaps understandable. This seventy-five-year old rivalry between the two clubs facing each other across the East River began with the Giants beating the Brooklyn Bridegrooms in the first World Series and has not yet abated, though the two clubs have moved to California. Allen's account, quite naturally, features colorful stories about such famous players as John J. McGraw, Willie Mays, Duke Snider, Jackie Robinson, Christy Mathewson, Roy Campanella, Sandy Koufax and many, many unknown knights of the diamond. In the old days Brooklyn was known as Trolleyville because of its maze of trolley lines and Brooklynites were termed Trolleyville because of its maze of trolley lines and Brooklynites were termed Trolley Dodgers. Giants were the aristocrats and the Dodgers, the traditional underdogs, were stamped as plebeian sandlotters and vulgar incompetents (""We wuz robbed!""), this last reaching its apotheosis in ""Lippy"" Leo Durocher who, when he crossed over to become a Giants manager, changed personality also, becoming ""The Little Shepherd of Coogan's Bluff.