Given the explosion of popular interest in the study of Kabbalah, and the unfortunate popularity of a slew of simplistic and distorted introductions from a new age perspective, it is particulary timely for a book of this quality to emerge.
The book is pleasantly designed and well-illustrated. It consists of dozens of short (but detailed) chapters which provide effective introductions to kabbalistic ideas... including many which are completely overlooked in some texts. The author is a legitimate academic, but writes in an extremely accessible style.
If you're looking for a book to get started with kabbalah seriously, I can't think of anything better than this. Skip the candy and go right to solid food!