This is really a 2-in-1: a manual of forensic psychological profiling and a masterpiece as a crime fiction novel. It works. I'm new to Val McDermid so have much to look forward to in this series, though I did not read the first. However it was easy to pick up the relationship between Tony Hill and Carol Jordan and their ghastly shared history. The detail is fascinating and it's not difficult to process the subtle differences as explained between MO and "Signature". I shall look for this in crime fiction from my other favourite authors. It's quite academic in parts where Tony Hill is explaining the finer points of profiling but VM does this so easily and so well. Her prose is excellent, her use of language demanding and stretching. Her characterisation digs into the core; there is nothing superficial here. But there are lots of twists and surprises. And what confidence to expose the murderer at the outset.