A collective melancholy hovers at the start of Richard Osman’s “The Impossible Fortune” (Pamela Dorman, 368 pages, $30), the fifth book starring the group of English senior sleuths known as the ...

How pervasive is the “Thursday Murder Club” universe? Consider this: The fifth book in the bestselling series, “The Impossible Fortune” (out Sept. 30), includes a joke about an actor who stars in the ...