- False Value, by Ben Aaronovitch. Gollancz. $29.99.
At the time of writing this review, Ben Aaronovitch's False Value was the number one bestseller on the Sunday Times fiction list.
It is the eighth in the 'Rivers of London' series, which mixes police procedural crime stories within an urban fantasy framework in the style of Terry Pratchett and Douglas Adams.
Indeed, Adams's 'Hitchhiker' novels are cross-referenced on a number of occasions in False Value.
The story sees suspended detective Peter Grant going undercover from his job in the Metropolitan Police.
Grant is hired as a senior security consultant at the London-based Serious Cybernetics Corporation (SCC), run by rogue Australian tech-entrepreneur Terrence Skinner.
He allegedly made his millions in Silicon Valley and is now funded by the Russians to uncover algorithmic secrets.
Grant is tasked to find out who is trying to kill Skinner and steal the secrets of SCC, which involve AI magical devices linked to Ada Lovelace, Charles Babbage and the 'Mary Engine', as well as mysterious rose jars, used for trapping ghosts, as key resources.
Grant encounters many hurdles, not least "a demon trap", a magical land mine which has to be defused by even more powerful magic. There are also problems posed by some competitive librarians from the New York Public Library who are after the same secret device.

Grant will need all his skills to thwart Skinner, uncover the truth and prevent the opening of a Lovecraftian portal into darkness in the SCC server warehouse.
Help is provided by his multicultural colleagues at the supernatural police headquarters, "the Folly", headed by "Detective Inspector Thomas Nightingale, a man who is looking considerably - indeed, suspiciously - spry considering he was born in 1900" and " DC Sahra Guleed, who wears a hijab with more stylish flair than anyone else on a Murder Team, who is still coming to terms with the fact that magic is real - and far from always benign.
Let's not forget Molly (no last name, at least none I'm going to tell you), London's most retro - and scariest - traditional house maid. She looks after the Folly, our heroes' home base in darkest Bloomsbury".
Aaronovitch's narrative pace stutters at times as he combines historical computing, contemporary hi-tech, police procedural and the supernatural, but a vigorous last third of the book brings it all to a rousing conclusion.
An added bonus comes with a new Aaronovitch short story at the end of the novel, 'A Dedicated Follower of Fashion'.