‘Newly discovered novel’ can be a discouraging phrase. Sure, some writers leave works of extraordinary calibre lurking among their effects — Flann O’Brien’s The Third Policeman, say. Other books, though, would have done as well to stay lost. Did the world really need to set eyes on Harper Lee’s first draft of To Kill a Mockingbird in the form of Go Set a Watchman? Probably not, although you can see why a publisher wouldn’t quibble with one more title from such a famous name.