No writer alive today is more fun for me than Anthony Horowitz. As he has said in interviews, Horowitz writes just for himself. He is not concerned with market trends. He is not looking for Netflix deals. He writes because he has to write. There is a well-populated world inside his head; he knows how to describe that world. His sentences are elegant, and his stories are surprising, well-structured, and weirdly plausible. The Horowitz/Hawthorne series uses a grammatical or writerly term in each title: "The Word Is Murder," "The Sentence Is Death," "A Line to Kill," "The Twist of a Knife," "Close to Death," "A Deadly Episode." In the newest novel, "Episode," Horowitz is filming a series based on his own books. There is an actor to play Horowitz's detective buddy, Daniel Hawthorne. When the actor is murdered, it looks like a case of professional jealousy "run amok." Is the killer a costar? An agent? A sc...