When Helene Hanff makes an innocent inquiry about the possibility of purchasing hard-to-find books through Marks and Co., Booksellers, she begins a 20-year love affair with Frank Doel, the proper English bookseller who answers her letter and sends along her first order in the fall of 1949. They are two very unlikely correspondents: she a cranky Jewish New Yorker who writes TV scripts and lives in a messy apartment on East 95th Street; he a determinedly courteous middle-class Englishman who sends