A series of
detective stories written by
Isaac Asimov. The Black Widowers are a
group of men who get together every month to have dinner and talk. One of them brings a guest, and after
dinner the guest is "grilled" - traditionally this begins by asking him to justify his
existence. The guest always turns out to have a
mystery to tell the club about, and after the Black Widowers have kicked the problem around, Henry, the waiter, always comes up with the
solution.
The Black Widowers club was formed because the wife of one of the members didn't get on with his friends at all, so they formed the club to be able to continue meeting, and it remained all-male even after she died. Its name derives from the black widow spider, because their females devour their mates and the Black Widowers were determined to survive.
Asimov got the idea for the Black Widowers from a real-life club called the Trapdoor Spiders which he belonged to (which also remained all-male even after the member whose marriage inspired it got divorced). The individual Black Widowers in the stories are based on members of the Trapdoor Spiders, but Henry is purely fictional. None of the Black Widowers is Asimov himself, but he sometimes appears as a guest or minor character.