Stretching Out a Good Story: Bruce Coville, My Teacher Glows in the Dark (New York: Harper Collins, 1991).

I wrote about the last of these a while back. Basically Coville has taken Heinlein's classic, Have Space Suit, Will Travel, spread it over five books and given all the interesting things to do to the adult aliens.

I like Coville's work but this series is dismal in the way it renders kids mostly as observers.