I ADMIT IT: I still haven't gotten around to reading J.K. Rowling's first post-Harry Potter novel, The Casual Vacancy, despite being a giant Harry Potter fan. But when news broke that Rowling had written a detective novel, The Cuckoo's Calling, under the pen name Robert Galbraith, I bought the ebook immediately. I feel the tiniest bit guilty about this—apparently I'm an unadventurous sort of reader, only willing to support an author so long as they continue to do just what I want them to do. And in Rowling's case, I want fun genre fiction, not dry-sounding literary novels about British council elections. Sorry, Casual Vacancy; I will probably never read you.

The Cuckoo's Calling is a character-driven detective novel, more "little gray cells" than CSI: London. Rowling's detective, Cormoran Strike, is a battered, one-and-a-half-legged veteran of the war in Afghanistan, a former military man who retired after his leg injury to become a private investigator. When the book opens, his business is foundering and Strike is newly homeless, having just broken up with his live-in girlfriend. A temp agency mistakenly sends him a secretary he can't afford on the same day that he's visited by a client who wants him to prove that a high-profile suicide, in which a supermodel was presumed to have jumped to her death, was actually a murder. Accompanied by his plucky new secretary, Robin, Strike takes on the case, which involves high fashion, drug-addicted street kids, beautiful women with mysterious pasts, and plenty more.

The most surprising thing about The Cuckoo's Calling isn't the tightly organized plot (the Harry Potter books were full of mysteries) or the compelling character dynamics (ditto), but rather Rowling's sense of humor, which is adult and sly and intelligently deployed. Take, for example, a joke about a red-breasted robin that is not only funny on its own, but deftly reinforces the initial awkwardness between Strike and Robin, two attractive straight people working in close proximity. Strike has the "high, bulging forehead, broad nose and thick brows of a young Beethoven who had taken to boxing"; "his thick curly hair, springy as carpet, had ensured that his many youthful nicknames had included 'Pubehead.'" Pubehead! J.K. Rowling said "pubehead"! (This is perhaps just the kind of commentary Rowling was trying to avoid by writing under a pseudonym.)

The Cuckoo's Calling doesn't revolutionize the detective novel, but it's a solid read that proves what Harry Potter fans have argued all along: That Rowling's a great writer whose novels shouldn't be dismissed simply because of the genre she's writing in.