The film""s screenplay (by Dorothy Yost and Mortimer Offner) was based on Jane Murfin""s adaptation of Booth Tarkington""s 1921 prize-winning novel of the same name about a girl in a mid-sized Indiana city.]The film""s frightening, daring, and far-fetched plot, from a screenplay written by co-producer and Broadway playwright George Axelrod (famous for the Broadway playWill Success Spoil Rock Hunter?andLord Love a Duck (1966)), was based on Richard Condon""s 1959 novel of the same name.Supposedly, the inhabitants of the destination were greater beings (or "Engineers") who created Earth and humankind, and then changed their minds and wanted to destroy humanity.Wilder effectively used locales in the greater Los Angeles area: the Glendale train station, the Hollywood Bowl, ""Jerry""s Market,"" a night-time downtown office building, a Spanish-style house on Quebec St.]During mail call, the men receive letters from back home - they have been written as part of a campaign to bolster warfront spirit: "Thousands of dames writin"" us thousands of letters hat are supposed to pep us up.