The finding of a magical charm that half-grants wishes, or grants half-wishes, gives four children the adventurous life they've been craving as they learn first to calculate their wishes precisely and then think about carefully about what they're wishing for. This is a light, breezy, fun and funny tale. I'm not sure I'd call it timeless as one or two old-fashioned attitudes might make a modern reader wince, but it's easy to be forgiving with a book this open-hearted and good-natured.