It is not difficult to see why Ben Aaronovitch's first novel, Rivers of London (Midnight Riot in the US, 2011) attracted so much attention. Aaronovitch coupled the idea of the breezy police procedural with that well-worked fantasy trope of secret London, creating a small and obscure special unit which lurks under the capacious aegis of the Metropolitan Police, and dedicates itself to investigating cases where the occult represents a clear threat to the citizens of London. It’s generally known as "the Folly," in reference to its base of operations, but implicit also is the idea that the continuing existence of such a unit is anachronistic nonsense. What place do wizards have in twenty-first-century policing? Obviously, given that Rivers of London was the first in a series, more than you might initially suppose.

The overarching narrative posits that while the use of magic might have dwindled after the Second World War (thanks in part to thousands of magicians, on both sides of the war, being annihilated during one particular battle), suddenly magicians seem to be active again, and their intentions are not benign. DCI Thomas Nightingale, a survivor of the Battle of Ettersburg, the only serving police officer who is also a classically trained wizard, and at the opening of Rivers of London, the only member of the Folly, finds himself dealing with an abnormal caseload as magic erupts all over the city.

Peter Grant, an enthusiastic but undistinguished probationary police constable, dreading an assignment to a desk job, is recruited by Nightingale after an incident in which Grant takes a witness statement from a ghost, following the unexplained death of a man in Covent Garden. This is followed by Grant's discovery that he is sensitive to the impressions left by the use of magic, all of which draw him to Nightingale's attention. By the end of the novel Grant has become a Detective Constable and is Nightingale's apprentice. Along the way, he has helped solve a series of supernatural murders, brokered a deal between Mama Thames, who rules over the tidal river, and Father Thames, who controls everything above Teddington Lock, to stave off a turf war across the city; variously made friends and enemies of Mama Thames's children, the rivers of London, accidentally burned down Covent Garden market, and at the close of the novel is wondering what to do about a man who has apparently had his penis bitten off by a woman with unusual dentition. Meanwhile, his colleague, Lesley May, has barely survived having her face destroyed by a magical creature.

Before discussing Moon Over Soho, the second novel in the sequence, it's worth considering the nature of the magic at work in the series in greater detail. When Nightingale describes himself as a classically trained magician, he is working with what he calls Newtonian magic, that is a formal system of magic drawn up by Isaac Newton (who was historically as much an alchemist as he was a scientist, a fact that still makes some modern scientists a little uneasy). We can only hazard a guess at Newton's intentions when he devised such a code. It suggests that an intuitive approach to magic has been replaced by something more mechanistic but also consistent, manageable, easily reproduced, in keeping with the development of new scientific methods. However, it would also be in keeping with the times to place a formal structure on magic in order to limit access to it, rather as a distinction was also being drawn at that time between herbalists and doctors, the latter seen as having a superior training.

In magic it would seem, as in everything else, that there are class distinctions, and this is implied in Rivers of London and its sequels. Nightingale, we learn, attended a boarding school for young magicians. Peter Grant, a child of his time, naturally fastens on Hogwarts as a comparison, an analogy wasted on Nightingale who has only the flimsiest grip on post-war culture and technology in all its forms. However, on a visit to Nightingale's former school, we have a sense that it was run very much along the lines of those public schools which are more familiar to us. Unsurprisingly, perhaps, given the boarding school ambience, formal magic seems also to be the purview of the male of the species. Although the series abounds with women with magical capabilities the implication is that they draw their resources from elsewhere. The assumption is that the British wizards who fell at Ettersburg were exclusively male, which might lead to some interesting questions about the hereditary nature of magical talent.

In a recent interview Aaronovitch said that one of the ideas driving the series is "suppose Harry Potter had gone to a comprehensive school rather than Hogwarts," a statement that might be open to various interpretations, not all of them positive. At the most basic level, Peter Grant is obviously no Harry Potter: he is of mixed parentage, grew up on a council estate in a family that is not notably dysfunctional, and had a state education rather than a private one, but he was clearly not a student without ambition. He enlisted in the police force only after his dreams of becoming an architect foundered on his inability to draw. As a police constable he is idealistically passionate about maintaining the rule of law but has so far been a square peg in a round hole, mainly because he is also blessed with an inquiring turn of mind.

In practical terms, this means that Grant is driven by a need to know, as he says to Nightingale when he is recruited. Yet, the driving force behind Newtonian magic is not so much one of wanting to know as one of acceptance, taking the magic for what it is, learning the spells or forma by rote, and drilling them endlessly until they become second nature. Newtonian magic is about learning Latin and Greek, reading the theory of magic, and immersing oneself in it from an early age. It is not a form of magic that invites either innovation or a late start. In many ways it appears to be a magic of birthright and privilege, and in fact not so dissimilar to that featured in the Harry Potter novels.

Neither does Newtonian magic appear to acknowledge the existence of the quantum age, something Grant quickly finds out the first time he uses magic and fries his mobile phone, because magic destroys microchips if power is flowing through them. Much of Grant's spare time is thus devoted to researching how to accommodate magic alongside twenty-first century technology. This says something else about the nature of formal magic. Without younger practitioners to innovate, it has become stagnant . . . until the arrival on the scene of Grant and the young magician, a practitioner of the dark side of magic, who will become known as the Faceless One, and take on a role as Grant's regular adversary. This represents another iteration of the class war, for the Faceless One appears to be a gentleman magician, Oxford-trained to boot, while Grant takes on the role of the scholarship boy made good but way out of his social depth.

Yet, for all his desire to innovate in magic, Grant is as wedded to the mechanistic as anyone else in his fervent belief in the structures of police work. Good police work, as he is fond of pointing out, rather too fond in fact, relies on a systematic approach. Effectively, this means admin, even if paper is replaced by computer databases, and Aaronovitch devotes many pages to lovingly describing the admin processes behind police work, to the point where many of his readers could doubtless run HOLMES, the police database, with little further tuition. This slavish devotion to admin, however much he may complain, sits curiously at odds with Grant's perception of the occult as somehow freeing him from conventional police work. His approach to the latter is as mechanistic as Nightingale's to magic, though in Grant's case, the end result in both police work and magic appears to be chaos.

Aaronovitch's approach to his novels is equally mechanistic. Even after a mere two novels, the formula is already quite obvious. Each novel has a theme, reflecting a facet of life in London. For Moon Over Soho, the theme is jazz, beginning when Grant is asked by Dr Walid, the Met's resident cryptopathologist, to listen to a body. Like Grant, Walid can pick up vestigia, and like Grant he has heard the jazz music that haunts the body of Cyrus Wilkinson, a jazz musician who has died for no obvious reason. This gives Grant carte blanche to wander around Soho, visiting those jazz clubs which still remain, hunting for more signs of magic, as well as unearthing some of the more presentable elements of Soho's history as a den of vice and iniquity. And even when Aaronovitch is dealing with violence, bloodshed, chimeric vivisection, people-trafficking, or multiple murders, he somehow seems to maintain a cheery demeanour, as if to reassure the reader that this is just fiction, and his fantasy London—even Soho—isn't that bad really, which is frequently strangely at odds with the situations he is describing.

Aaronovitch clearly enjoys his research and enjoys sharing the results of his work. However, he does not always wear his knowledge quite as lightly as one might hope for; in the nicest way possible, he is prone to offering the reader expository lumps of London history. One's tolerance of this may well be related to how much one already knows about the history of London, which may in part explain the series's huge success.

Rather like Newtonian magic there is a certain flavor of the rote about Aaronovitch's plots. Each novel includes a sequence about magical training, a section about police admin, a section on Grant's on-off relationship with Lesley, a glimpse of the history of magic filtered through Nightingale. Each novel also features at least one prolonged and bungled chase sequence, often more than one, as well as a set-piece in which Grant inadvertently damages or destroys another London icon. In Moon Over Soho, his encounters with the Pale Lady, she of the unusual eating habits, cause mayhem in Westminster, the least of which is the hijacking of an ambulance and crashing it into the Thames to save the life of Father Thames's son, Ash.

Yet there are moments when Aaronovitch seems to transcend his own formula. These occur almost every time one of the rivers appears. For example, Lady Ty—Tyburn—has a regular slot as an ambitious Blairite political wannabe, with an eye on taking over the regulation of magic, and her exchanges with Grant fairly crackle with malign energy. In Moon Over Soho, this extends to Simone Fitzwilliam and her "sisters," Peggy and Cherie, who are, Grant comes to realize, somehow associated with the string of unexplained deaths among jazz musicians that he has uncovered and who, as he ought to have long since realized, are feeding on the sexual energy of Soho itself. "Jazz vampires" they may be, but as Grant finally comes to understand their nature, Aaronovitch handles their own realisation of their predicament with an extraordinary tenderness which is a stark contrast to the bright and breezy tone we associate with Grant. It may be that Aaronovitch is keeping a firm grip on the idea that police officers cope with the horrors they confront every day by maintaining a professional detachment but one could occasionally wish that Grant would show a little more psychological depth rather than facing everything with such disturbing equanimity.

There can be no doubt that Ben Aaronovitch has found a winning formula with this series. The novels are slickly written, entertaining, funny even, and they're about London. What's not to like? But that is the problem. Given its constituents, I ought have enjoyed Moon Over Soho rather more than I did, but something is lacking. In part, it is a little too formula-driven for my taste but mainly I think it is that the novel is all surface. It is a beautiful surface, well polished and very shiny, but it conceals very little. London itself is a city of many layers but with Peter Grant's London, what you see is what you get, and somehow it is not quite enough.

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