The 1980s saw the emergence of New Age and neo-paganism as major new religious movements. In the first book-length study of these movements, Michael York describes their rituals and beliefs and examines the similarities, differences and relationships between them. He profiles particular groups, including the Church Universal Triumphant, Nordic pagans, and the Covenant of Unitarian Pagans, and questions the adequacy of existing sociological categories for describing these largely amorphous phenomena.
OK, it's pretty clear that this book is a doctoral dissertation - so from the outset you know this isn't a light read. But with that said, Michael York sets out and does something for Pagan theologies which hadn't really be done before - explain where they fit in - from more of a sociological and comparative religious standpoint than necessarily a purely theological one. Not only that, but he does it (because it's written to be 'defense-able') in a way that isn't just a collection of suppositions, but is painstakingly documented and cross-referenced. I found his concept of SPIN (Segmented Poly-centric Integrated Networks) a novel and very useful explanation of how Pagans view (and treat) leadership, and have seen his ideas laid out in this book gradually seep into other Pagan writings (usually under more user-friendly terminology) in the intervening 15 years since this book came out. This is an important, but not easy, book to read if you want to understand the development of modern Pagan culture. (It should also be noted that he gives the creation and early development of CUUPS a few pages in the book.)