Promoting what is arguably the greatest horror film of all time, Bill Gold’s poster for The Exorcist just oozes dread in every inch, from its single image of Max von Sydow’s Father Merrin arriving at the MacNeil house to the purple font and lower third, to the two-sentence-long plot synopsis: “Something almost beyond comprehension is happening to a girl on this street, in this house...and a man has been sent for as a last resort. This man is The Exorcist.” You can practically hear the piano begin to play.