The 2nd book in Aaronovitch's series which mixes urban fantasy and crime fiction. Follows the success of "Rivers Of London", and features Peter Grant, an apprentice to the last wizard in England and a Detective Constable. With appeal to fans of Jim Butcher's "The Dresden Files" and Mike Carey's "Felix Castor".

Before becoming a bestselling author, Ben Aaronovitch was a screenwriter for Doctor Who and a bookseller at Waterstones. He now writes full time, and every book in his Rivers of London series has been a Sunday Times Top Ten bestseller. He is published in 14 languages and has sold more than 2 million copies around the world. Aaronovitch is also a trustee on the board of Cityread London and is a long-time supporter of Nigeria's premiere arts and cultural festival, The Aké Festival. He still lives in London, the city he likes to refer to as 'the capital of the world'.