A British family found a baby boy on their front steps:
Sorry, I got carried away: wrong story. The beginning was similar enough to that of Harry Potter story, so it is easy to make a mistake.
A recent widow of a bestselling American writer found a baby boy in her vestibule with the note attached to his cloth saying that a boy should live in his father's house. Her late husband was not exactly shy when it came to women, so it was quite possible the baby was his - may I remind you the book takes place in early sixties, before DNA tests were developed.
Naturally the widow was curious about the baby, but she wanted to avoid the publicity of the situation, so she came to Nero Wolfe asking him to find the baby's mother - she wanted to see her for obvious reasons. By the end of the book not only she did not avoid the aforementioned publicity, she was put right in the middle of a spotlight.
So seemingly harmless investigation turned from this:
into something more similar to this (what Archie Goodwin calls Mother Hunt):
The detectives have to deal with obsessive button collectors, hundreds of potential young mothers, some dead bodies and have to run away from the police for an icing on the cake. So yes, this is one of the rare occasions where Wolfe not only has to lift his behind and get outside of his house, but also has to move really fast doing it (he can if a great need arises).
This is a very good mystery book with some unexpected twists along the way. Archie Goodwin's usual witticism shines and makes the story really come to life and always keeps it from getting boring, even on the occasions where the detectives come to a dead end in their investigations - and they do it fairly often here.