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  === Ratings ===
  "Book of the Stranger" was viewed by 7.82 million American households on its initial viewing on HBO, which was slightly more than the previous week's rating of 7.28 million viewers for the episode "Oathbreaker". The episode also acquired a 3.9 rating in the 18–49 demographic, making it the highest rated show on cable television of the night. In the United Kingdom, the episode was viewed by 2.775 million viewers on Sky Atlantic; it also received 0.116 million timeshift viewers.