First novel from John Verdon and he has come up with a prettty full on story. Verdon's main character, Dave Gurney is an ex-detective enjoying his retirement and passing the time creating artworks which involve portraits of killers. He is contacted by a guy named Mark Mellery who he used to go to college with, and who has just recieved a strange and threatening letter and Gurney gets pulled in and before he knows he is back trying to make some sense of a brutal murder. Edgy and well paced Think of a Number has all the makings of a bestseller.Good sort of book to settle down with if the weather closes in.