This isn't really a crime novel, unlike Simenon's other romans durs I've read. But it is the same fleet, finely tuned writing that says so much more about isolation and alienation than what appears on the page.
Jeantet's carefully constructed life begins to crack when he arrives home to find his wife missing. The book's title answers whether or not she will be coming back.
Throughout the story he often tells himself that now he is a widower. For him that word becomes a process, as little by little it's revealed to him what exactly has been lost.
Given that in real life GS could be a jerk toward women, his portrait of Madame Jeantet is sensitive, respectful.
Not Simenon's best perhaps, but his near misses are still damn good.