 The original screenwriter was Len Deighton, who accompanied Harry Saltzman, Syd Cain, and Terence Young to Istanbul but he was replaced because of a lack of progress.Thus, two of "Dr. No"s writers, Johanna Harwood and Richard Maibaum, returned for the second film in the series.Some sources state Harwood was credited for the "adaptation" mostly for her suggestions which were carried over into Maibaum's script.