Their names alone evoke glamour: Oona O'Neill Chaplin, daughter of playwright Eugene O'Neill and child bride of Charlie Chaplin; Gloria Vanderbilt, heiress to one of America's great fortunes and fashion empress in her own right; Carol Marcus Saroyan Matthau, wife first of one of America's most beloved writers, later of one of Americas most successful actors. What few people know about these very public women is the very private friendship that has...