are there any books related to the series?
Yes, "Inside Black Mirror"
Black Mirror
In June 2018, Brooker announced that he, along with Annabel Jones and Jason Arnopp, have written an oral history companion to the series titled "Inside Black Mirror". 
what is the meaning of metalhead in black mirror UNANSWERABLE who has written this episode? Charlie Brooker how are the reviews of this episode? It received mostly positive reviews, on Rotten Tomatoes, the episode has a score of 67% based on 24 reviews, with an average rating of 6.87 out of 10. which series does this episode belong to? "Black Mirror" what genre is this series on? British dystopian science fiction anthology television series when did netflix take over this series? September 2015 who aired the show before that? Channel 4 is there a movie under this series? Yes, "Bandersnatch"
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Black Mirror [SEP] Literature
In June 2018, Brooker announced that he, along with Annabel Jones and Jason Arnopp, have written an oral history companion to the series titled "Inside Black Mirror". The book features sections on each of the 19 episodes in the first four series, containing conversational interviews from cast and crew and images from the episodes and behind the scenes. The book was released in the UK on 1 November 2018 and in the US on 20 November 2018 from Penguin Random House. "Starburst" rated the book ten out of ten stars, praising its "wonderfully-comprehensive format" and summarising it as "blunt, brittle, often killingly funny and lavishly-illustrated".