In the opening song sequence , Sharmila Tagore is seen reading a book while seated in the train. The book's name is When Eight Bells toll, a thriller novel written by Alistair Maclean published in the year 1966. The film was released in 1969, so it is clear that the flashback was shown in a time which was actually a "flash-forward", which is impossible.She should have been shown reading The Heart of the Matter (1948), a novel by the English author Graham Greene.