Graham Greene's "___ Man in Havana"

OUR

This 1958 spy novel follows a vacuum cleaner salesman turned reluctant agent in pre-revolution Cuba—look for the possessive pronoun in the title.

This clue references the title of Graham Greene’s 1958 novel Our Man in Havana, a spy story set in Cuba. The blank in the clue hints at the missing first word, which is "Our"—so the answer is simply the three-letter word that completes the title. It’s a straightforward fill-in-the-blank with no wordplay, just a test of literary knowledge.