Harry Potter is gone. In his place is Jackson Brodie with a peg leg. JK Rowling (for it is, we know, following the slip of a lawyer’s tongue, she) has written a novel about a private detective under a pseudonym. Like Kate Atkinson’s hero Brodie, Cormoran Strike (yes, really) has an army background (losing a fair bit of him below one knee in the process), a colourful personal life and an ability to get on with women which is unusual for other fictional characters in his line of work, and may have something to do with him being written by a woman. The plot: beautiful model Lula Landry has committed suicide, leaping from her luxury Mayfair apartment. The police have shut the case. But her half-brother (Lula was adopted) is convinced there is more to it. And, of course, he is right. Strike – who despite sleeping on a campbed in his Soho office and appearing pretty much down and out – has some experience of the glamorous world which Lula inhabited and possesses, of course, a razor-sharp intuition (without which the plot would be lost). If you start from the basis – always a good first principle – that the least likely suspect will somehow have done it, the malefactor is relatively easy to spot. But the why and the how are ingenious and – just about – plausible. Rowling plays fair with the reader, leaving at least the majority of clues out in plain view. Perhaps the best recommendation anyone can give is this: I would happily read another case involving Strike and his delightful (female) assistant, Robin, who have a sprightly, fairly believable chemistry between them. There is a school of thought which suggests Kate Atkinson became a better author when she started concentrating on crime fiction. This isn’t anywhere near as sharp as Atkinson at her best: The Cuckoo’s Calling is too long, for one thing. But, perhaps freed by being ‘Robert Galbraith’, Rowling has taken the best of the adult writing she demonstrated from the moanfest that was The Casual Vacancy to create an intricate tale which follows the rules of the genre yet remains a pleasure to read. Her best novel by a distance.