I'm reading several Enneagram books at once right now, so my review may be giving some credit for another book to this one, but this is a great basic, but really solid overview of the system. I have been so excited to see my interest in human behavior models converge with my spiritual beliefs. This system is very useful as a secular tool, but is even more powerful spiritually. It's applicable to many religious contexts. I'm looking forward to reading the book I have about the Christian Perspective, as well as Facets of Unity.