I've been a fan of this series ever since I abused my privileges as a student librarian at school to take out as many books as I liked without fine if I brought them back late. I read the first three books then, and honestly thought that was the entirety of the series. Imagine my shock when I recently found a further four books! Having read through them and this, the most recent addition, Ms. Duane's status as one of my favourite authors has not been altered. I've always been impressed with how 'realistic' the usage of magic is; every usage has a consequence, nothing is trivial and there is a healthy dose of science fiction in the mix with the depiction of other planets.
This book is perhaps a bit lighter on an underlying theme than previous books in the series, perhaps due to two different storylines going on at once. With the same amount of space being handed to two stories, I will admit to feeling not as involved as I have in the past. Still, there does seem to be a great deal of foreshadowing for something going on, presumably to be depicted in the next book, which is left unexplained at the end. Indeed, it does seem to end a little abruptly, with points left hanging. And what story there is doesn't really start to get going until quite late on in the book, with the majority being set-up, it seems. It means that this book, while very enjoyable, isn't my favourite of the series.
JK Rowling has her startling popularity, but I've always found Diane Duane's depiction of wizardry to be far more interesting. I'd recommend this to any teens (or adults who can look past the 'young' label and realise this is a very good series) who want something a little more challenging.