“Cloud Cuckoo Land,” by Anthony Doerr (Scribner)How do you follow up a Pulitzer Prize-winning work of fiction? If you’re novelist Anthony Doerr (“All the Light We Cannot See”) you write a story that consists of five separate stories, spans millennia, and all ties together with a fictional manuscript attributed to the ancient Greek novelist Antonius Diogenes called “Cloud Cuckoo Land.”Sound a little, well, cuckoo? It sort of is, but it’s also admirable in its ambition.