This is a gripping, funny, and sad story about a sick boy. As a comment about how mental patients were treated at that time, it's an important work. It's all the more beautiful when you know that the main character actually lived, and was the author's brother.
The first time I read it, was in Icelandic 101. That is not recommended. A crazy person talking about what happens in his head, in a language you are trying to learn, is not a good combination. ("Did he really just say 'open a barber shop on the moon', or have I completely misunderstood some words here...")