Italian polymath Umberto Eco made a dazzling literary debut more than twenty years ago with The Name of the Rose, and he  retains an outsized ability to make readers stand up and take notice. In Italy his new novel, The Prague Cemetery (Houghton Mifflin Harcourt, $27), has stirred some controversy as being anti-Semitic, but I strongly disagree. (Publishers Weekly describes the book as “hilarious.”) The main thing you need to know about Eco is that his academic field is semiotics, the study of signs and symbols. This informs his fiction, especially here, where the narrator is a master document-forger, thus casting a shadow of doubt over everything he recounts. For instance, how much can we trust the story of a meeting of the leaders of the Twelve Tribes of Israel? They are said to have gathered in Prague’s Jewish cemetery to plan a Jewish conquest of the world, but the whole plot is called into question once the narrator has confessed that he falsified oral testimony given by a secret witness to that meeting. The narrative chronicles a paranoia so outlandish, and conspiracy theories so abundant, that the novel is as humorous as it is ominous about the darker forces of human irrationality.