291Y: Father benignly deceives son

I’m looking for a chapter book in which a father amazes his son by seeming to do a magic trick on a city block, involving a building which is either being built or torn down. The father doesn’t really do anything magical–he just has information that the son doesn’t, so he can frame it as something enchanted. The son totally believes the illusion and is in awe of his father. This episode, which extends over several weeks, is a plot point in a book that I don’t think was aimed at kids or YA but involved children. It was written, perhaps, in the 60s or 70s? I thought it was by William Goldman, but I haven’t been able to find it.

291U: It definitely wasn’t Harriet the Spy

I’m looking for a book I read as a child in the 1960s. My clues are very vague (sorry!), but here goes:

The book was a middle-grade novel about two girls who play at being detectives. They follow people around and write in their notebooks. I thought the title was The Key House Mystery or The Key-House Mystery (with a hyphen), but I haven’t found it on sites I’ve tried.

Unfortunately, that’s all I remember.  I don’t know the color of the cover, whether there were illustrations, or when it was published.

The book definitely wasn’t Harriet the Spy.

291P: Suddenly No Men on Earth/No Women on Earth

I read a science fiction book in high school (1969-1973) about some kind of catastrophe that resulted in the sexes living in separate worlds. In the “Women’s World,” planes fell out of the sky.  Maybe the women didn’t know how to operate heavy machinery?  In the “Men’s World,” other things happened because they were lonely…?

I found it totally mesmerizing at the time.  I thought it had a title like “Island of Vipers,” but I have never found that title.  All help appreciated!

290R: A painter on a houseboat

I was born in 1965 and remember this book from when I was around 5-7.

It was about a painter that lived on a houseboat and painted abstract paintings. For some reason he broke the painting up into a bunch of small paintings and a buyer flew to his houseboat by seaplane to buy them I think the houseboat was near San Francisco. It was a large book, hardback, and illustrated.