Can an anonymous letter scare you to death? It turns out, yes - if you have something to hide, and the writer of the letter reads your thoughts. Having received such a message, Mark Mellery turns to an old friend, a famous retired detective, for help. David Gurney, for whom every crime is a puzzle, finds the perfect opponent: a murderer who loves to ask riddles. Each unsolved mystery leads to a new victim. However, Gurney continues to play... American writer John Verdon's debut novel, Make a Number, is a classic thriller. An impeccably constructed plot, carefully written details, recognizable characters and life collisions add up to a narrative that will take your breath away.