Well, that was a thing. I’ve been a fan of A Wrinkle in Time and A Wind in the Door since I was seven years old, and when I saw this at the library, I just thought, why not?
Basically, this is a short story L’Engle wrote for Children’s Book Week back in 1970, before she’d figured out all the pieces she needed to make A Wind in the Door a full novel. Progo and Sporos are there, the scene where Meg has to Name Mr. Jenkins is there, and honestly, there are significant portions that she reused with little to no alteration in A Wind in the Door. But she clearly hadn’t come up with farandolae yet, or developed the echthroi (though the seeds are there), and there’s no hint of Charles Wallace’s illness. It’s interesting that at one point she intended to revisit the Mrs Ws since as a kid I was always a little miffed that they were never really even mentioned again.
I do feel like the way this is republished is super misleading. It’s cool that they did republish it because beforehand, it was rare, but they tout it as a standalone “A Wrinkle in Time” story and act like it’s a full part of that world, but it’s not. It’s very much non canon and you absolutely cannot read it without having read the original book (and imo you shouldn’t be reading it without having read A Wind in the Door either because there are things that really just won’t make sense—mostly because they’re severely underdeveloped).
So basically, if like me you’re the kind of person who enjoys reading early attempts at the books that shaped your childhood (like the LeFay fragment for Narnia), it’s an interesting read. I’m also a writer myself, so that’s probably why it’s interesting to me to see early attempts that haven’t quite taken shape yet. But if you’re a non-writer and/or a casual fan, you’re just going to be confused by this. Go read A Wind in the Door instead. It’s a fabulous book and develops the ideas she began to play with here in a fuller, better way.