Read the Nada comic that Carpenter based the movie on
Background: https://dangerousminds.net/comments/the_sci_fi_comic_book_story_that_inspired_they_live
Ray Nelson’s short story “Eight O’Clock in the Morning,” on which John Carpenter based They Live, was first published in the November 1963 issue of The Magazine of Fantasy & Science Fiction. But Carpenter first encountered the story 23 years later, in its comic book adaptation, “Nada.”
Ray Nelson’s bio is recommended reading. He claims to be the inventor of the propeller beanie and says that, as a young man, “he worked with Michael Moorcock smuggling Henry Miller books out of France.”
Gruesome comic: https://sapcomics.blogspot.com/2012/01/nada.html (7 pages)