A lot of this information is already out there in some form or other in other books or on the web. However, this book organizes all that into something that is clear and concise. It's less wide-open drumming enthusiasm and more practical approach to making a great event.
For those of you who aren't familiar with Christine, she's a Music Therapist who is on Remo's HealthRhythms staff. The book draws largely on her partnerships with music therapists, researchers, and health and wellness folks such as Dr. Barry Bittman, Will Schmid, Barry Bernstein, Robert Lawrence Friedman, and others.
At less than 100 pages, it's fairly pricey for a little book ($15) but does include a CD. Speaking of which, the CD is frequently referenced in the book (things like "for an example of this technique listen to track 9. You'll hear the interplay of conga v. djembe that illustrates....").
For drum circle facilitators, this is the stuff! Add this one to your collection.
"In a drum circle, if you can't see the drums, all you see is a group of people working together, expressing their unique voice in a group song, united by a common pulse." - from the book.