The detective novel The Cuckoo’s Calling by Robert Galbraith — who was unmasked a few days ago as a pseudonym for J. K. Rowling of Harry Potter fame — doesn’t provide the reader with many clues to its author’s real identity. There are no wizards, witches or dementors in this novel; no magic or sorcery in its plot. Instead, the book is set in an all-Muggles London and features a disheveled, Columbo-esque detective named Cormoran Strike who takes on a case that plunges him into a posh world of supermodels, rock stars, movie producers and social-climbing wives.