The name of the story that I’m thinking of is apparently notThe Door Into Summer, as I’d been thinking for decades now.
This was an entire novel, and it was written no later than the '70s, since I read it as a child/teen. It was probably what would be called YA today, and in the Science Fiction genre (probably). The only details I think I remember is a strange boy (maybe 12-ish?) appears and interacts with another 12-ish boy and his family. The boy came through a door/portal, possibly from the future, possibly from another world entirely. The family in question may or may not have seen this. In the end, the strange boy is able to get back to his home.
I haven’t actually read Heinlein’s The Door Into Summer, but the synopsis seems to be a very different story than what I’m thinking of. So.
Thanks in advance, and I’m now starting the Countdown Clock to see how long it takes Our Legendary Dopers to answer this one.
Probably not The Forgotten Door since it didn’t involve the main character connecting with another boy his own age to any significant extent.
Forgotten Door was set in Appalachia; boy got adopted by a man and his wife (principal characters) and their children (NOT major characters, a boy and a girl). He can jump. He can read minds. The whole family escapes along with him to his world of origin at the end.
I do believe it isThe Forgotten Door. Reading a synopsis, I remember the name Jon, sticking in my memory because I believe it was the first time I saw it spelled that way. The publishing year (1965) and the length (about 140 pages) also match what I only vaguely remembered. Plus Alexander Key wrote several works aimed at juveniles, apparently.
Too bad this new forum doesn’t show the exact minute of posting, so I could see how long it didn’t take for my question to be answered. Or does it? Maybe there’s a setting I’m unaware of, that I could change?