As for the book - it's definitely meant for kids. There isn't much character development and the plot is very halting and has many holes. The whole thing was wrapped up on the last page, almost as an after thought.
There were some parts that I found hard to follow (not because of the concepts or plot, but because of the writing). The author uses many old-fashioned words/sayings and almost a backwards way of writing that make it tough to read (i.e. "who could bear being left out of happiness not one second longer" instead of "who could not bear being left out..."). I found myself having to re-read sentences many times. Because of this, I think reading this book to a child would work much better than having them read it alone.
A fun read - but definitely more for the kids, or if you read this book as a child yourself. I have bought the whole series, but am not sure if I will read the others (perhaps when I can read them to our kids). 3 out of 5 stars.