In 2013 when J.K. Rowling first donned the pen name Robert Galbraith, something about it didn’t quite make sense. Some reviewers pointed to Galbraith’s prose, which was clearly far too polished to be the work of a first-time writer. Others sensed the presence of a well-oiled publicity machine that couldn’t possibly belong to a writer who seemed to have come out of nowhere. Robert Galbraith couldn’t possibly be Robert Galbraith. In Rowling’s latest book as Galbraith, Lethal White, the truth is plain as ever. Rowling deftly circumnavigates all of the tropes and constructs that have long since relegated the male-author-dominated thriller genre to a place of ridicule and sheer inanity. It elevates the form from a place of predictable stodginess. Which is to say, Rowling outed herself the moment she managed to write a thriller that wasn’t steeped in a tradition of misogyny.Lethal White tells the story of a famous London private detective, Cormoran Strike, and his protégé, a young woman named Robin. The book begins shortly after Strike and Robin have apprehended one of London’s most notorious serial killers, the Shacklewell Ripper. Before long both Strike and Robin are sucked into the wake of yet another murder mystery scheme, this one spanning many years and implicating a series of politicians along with a radical socialist organization. Strike and Robin’s adventures have already been turned into a television series. By the time Rowling is done with them, the pair will probably become one of the most memorable duos in the entire genre of thriller fiction.A large part of Lethal White’s success is due to the fact that Rowling writes true to the form of a thriller, paying dues to its many constraints, while also subverting the most outdated tenets of the genre, namely in her treatment of women. In Lethal White women aren’t blunt objects used as plot devices or for the amusement of men. In today’s thriller fiction, half of the world’s population is basically represented as a nonentity, which doesn’t make for very compelling fiction. It barely makes for readable fiction. If Rowling can get away with writing almost 700 pages it’s because she knows how to untie a mystery at the right pace, and also because she has populated the world of her book with actual, three-dimensional characters.There are no scenes in which Robin stands in front of a mirror pinching her belly fat and wondering where the years have gone, as you will find in almost every thriller whenever a female protagonist gets a moment to herself. Robin doesn’t have extended meditations on her own breasts—scenes that are endemic to the genre but which could only ever have been written by a guy trying and failing to capture the psychological preoccupations of women, often helped along by an even more tenuous grasp of anatomy. It is a trope as old as time. In Lee Child’s The Affair, for example, a woman’s breasts literally burst a button on her shirt: “The button popped open, helped on its way by the swell of her breasts.” Or from Chris Pavone’s The Expats: “Her legs had always been one of her best physical assets. She’d often wished for fuller breasts.” This is about as much depth as the thoughts of women protagonists are allotted.Most importantly, Robin herself is not a mere plot device, but an actual character with a complex internal life. Rowling’s greatest gift to Robin is that she bestows her with flaws that thriller writers usually reserve for male protagonists alone: Robin stays in a relationship she doesn’t love because it’s convenient, she dreads playing out a polite charade with people she can’t stand—she is even petty at times. When we realize that she has feelings for her boss, Cormoran Strike, it isn’t because the author simply said so. It certainly isn’t because Strike is oh-so sexy. Robin’s affection for him makes sense because their entire relationship is predicated on a real, palpable, intense form of intimacy rooted in shared experience. We as readers see this entente as a real part of the story, and we see them as two people who care for one another rather than as vehicles for a steamy sex scene.Robin is also mentally tougher than most of the men we meet in Lethal White: She has PTSD, but from having been stalked and stabbed by a serial killer, not because she’s delicate.The flaws of male characters are also more credible in Lethal White than they are elsewhere. In many thrillers, the flaws of male protagonists all ultimately boil down to the idea that they are too charming. They have short tempers, which inexplicably makes women feel safer. They use impressive, obscure martial arts maneuvers to disarm an enemy in public. But in Lethal White Strike is not exceedingly charming in the traditional sense. He is a battered man who eats too many chips and has a missing leg. In Lethal White, men pick fights with other men in public and end up embarrassing the women they’re with rather than impressing them.And while many thrillers are still preoccupied with international espionage ploys against the West, Rowling’s political thriller is, at heart, a domestic thriller. It’s the story of business partners and relatives trying to kill one another. There’s no safe house in Bern, no mole in the Lubyanka, no rifle scopes hazed over by an incoming sandstorm in some remote desert. Even the politics of Lethal White come with a degree of nuance and relevance that is rarely, if ever, seen in recent thrillers from the last few decades. In Lethal White, one of the socialist leaders is a known anti-Semite, and Rowling suggests that when people say they’re anti-Zionist, it’s often just thinly veiled anti-Semitism, which is something most people seem too scared to say. Rowling, who spoke out against the Israeli cultural boycott understands that this lesson is a particularly important one for her readers in the U.K., where many people lean very heavily on this distinction in order to obscure acts of anti-Semitism.In that way, Lethal White serves almost as a treatise on the thriller genre as a whole. By wearing all the trappings of a traditional detective novel, it is able to mask how strangely revolutionary it is. Rowling covertly shows us each of the changes that this genre so desperately needs. If something about Robert Galbraith seemed to jump off the page when he first came on the scene five years ago, it may have been the fact that readers were unknowingly watching as Rowling dragged the genre into modernity in ways that were as unexpected as the sudden appearance of Galbraith himself.***Read Alexander Aciman’s Bookworm column in Tablet magazine on Mondays.