Think of a number
Before John Verdon wrote this, his first, psychological thriller about a serial murderer, he worked in the advertising business in New York. And like his hero Dave Gurney, a former NYPD detective, Verdon retired and moved to rural upstate New York. And probably also like his hero, Verdon has a troubled relationship with his wife.
Gurney is a very reserved person, who is excellent at logical reasoning, but not as good at human relationships. Still he is a likeable if distant character. He retired because his wife thought the job was eating him up, and although he had been sensationally successful in solving several complicated cases.
Now, in his rural refuge, his mind is running empty and when a former college friend asks him for his professional help, Gurney is gradually drawn into a complicated set of riddles, poems and murder, just the thing he likes.
But with all his intellectual finesse he does not see the obvious, and for once the reader finds the killer sooner then this just too brainy detective. And the reader likes it, even if the showdown is disappointing. First Verdon describes the murderer as a superbrain, and in the end he acts super stupid. Well, it is a first for Verdon.