This is book 18 of the "Nero Wolfe" series.

This note does not contain major spoilers for the book.

Yes, if there is a number in the title of a Wolfe book, you can pretty safely assume that it's a collection of that many pieces. The odds are very good that the number will be three.

The first story was originally published in 1949. In it, New York City residents casually purchase, own, and carry handguns for their personal protection when they think they need them. It's sure a good thing that they can't do that any more; it makes everybody so much safer. Some quick googling seems to suggest the "Sullivan" law that started the process was passed in 1911. I wonder if those common handguns that the police take no exception to are all illegal, or if it took a very long time for the law to really start outlawing guns, or what?