I had a hard time warming up to this book. I wanted to love it because MacDonald's "The Princess and Curdie" was one of my childhood favorites. The fantasy elements of the story are very original, whimsical yet deep, for the most part beautifully written, though there's too much tedious poetry interspersed. (I love poems, but not the kind that are in here.) 
 It's the book's philosophy that I struggle with. Your reaction will depend on whether you find it comforting, or morally offensive, to imagine that a divine being intentionally sends suffering to innocent people in order to bring about some greater good. This neat micromanagement is not part of my current concept of God. 
 I also have reservations about sharing this book with children because Diamond, the main character, is not a healthy role model for a real child. He caretakes all the adults around him, never asking anything for himself, and doesn't express disappointment or anger or impatience at what is a rather miserable lot. In the beginning, when he is more normal, North Wind reprimands him for feelings that would be perfectly appropriate in a child his age, such as fear of heights and not immediately trusting a strange woman who forces her way into his bedroom. After his mystical experiences, he becomes an adult's perfect fantasy of a child who will inspire them without having needs of his own. 
 (And while I'm on the subject, if his parents are so poor that he has to drive a cab while he's still in short pants, why do they keep having children? Rhythm method, anyone?)