A book I first read as young teen or junior high kid.
I didn't read a lot of fiction by Alice Mary Norton, AKA Andre Alice Norton, AKA Andre Norton, but this got reread many times. It's set in a scary and dangerous post-apocalyptic America, but it has a hopeful message that appealed to me after all the scary parts.
I originally read a copy from the library (the hardcover on the left). Later a friend of my brother's gave me the paperback on the right. (Note the change in title for the later edition.)
I still have the paperback edition on the right. I last read it maybe three years ago.