Gerald Corey is an author, consultant, counselor, and educator. He is a Distinguished Visiting Professor of Counseling at the University of Holy Cross.
It's a helpful book on techniques and tools for faciliating groups but it is DRY. Don't try and read it at night because it comes with a gaurantee to put you to sleep. But it is a good tool for individuals who lead groups of any kind.
Really useful book. If it were not a textbook, it would be more affordable and I would purchase my own copy. $50 for a used copy of a book only 1/4 inch thick?!