Will we ever live to see a successful screen adaptation of a Terry Pratchett novel? The Amazon television series Good Omens, which ended this month, came closest—but that book, a comedy about an angel and a devil teaming up to avert Armageddon, was co-written with Neil Gaiman, and the source material ran out after the first season in any case. Pratchett is the funniest English writer since P. G. Wodehouse, with a sharp, satirical edge disguised by the trappings of the fantasy genre—vampires, dwarfs, witches, and wizards. Many fans thought the original covers of Pratchett’s novels went too heavy on busty maidens and strapping men with big swords, undermining their literary merit, and a similar problem has beset the various screen adaptations from Sky and the BBC. I suspect that casual viewers can’t compute the idea of watching something with the comic tone of a Charles Dickens or Tobias Smollett novel while being distracted by CGI trolls. To some extent, Good Omens bucked the trend because the chemistry between the lead actors, Michael Sheen and …