I think all I can say about this book is that it was OK. The magic as described by Duane is interesting and definitely more complicated than the usual D&D kind, and Fred the white hole is a delightful character. However, both the main characters and the story felt a little flat, even as they were carrying an impossibly powerful item and fighting against a Lucifer figure. At first I also thought that my ebook edition was missing a few pages because the ending was so sudden.
This is a book that came out in 1982 and the YA market has changed a lot since then, so maybe the series got better in time, but as a standalone it's not very satisfactory.
Interesting premise, but it did not have the richness of Harry Potter and did not appeal to me. I doubt I will read the others in the series.