It was one of four films starring Dean Martin as Helm, and like the other three films the filmmakers chose to make the movie into an action comedy only very loosely based upon the novel (no incident such as Helm's accidental beating death of a female agent occurs in the movie).
Dean Martin starred in one of four movies about Helm. The filmmakers chose to make these films primarily an action-comedy, but they did not follow the book closely; for example, Helm does not die by accident in the movie.