Jonas is looking forward to starting school. But he doesn’t know how to read, the letters don’t make sense to him so he cheats by learning everything by heart at home. When he is found out in second grade, the teacher wants to send him to the other school, where all the dumb kids go. So Jonas runs away.
“Every new teacher should read this book”, according to the Chicago-Sun-Times praise on the book’s cover. And I agree that it would have been true at that time, but I’m not really sure if it still holds today. The characters in the book are definitely interesting and I actually laughed out loud a couple of times, but it doesn’t focus as much on Jonas as the title indicates. You don’t really get to know Jonas.
The book has been published in English, probably some time in the fifties, so if you come across it, you should read it.