"The New Encyclopedia of the Occult" is archdruid John Michael Greer's survey of Western occultism, although a few entries on Hoodoo have been included, as well. The author, apart from being the current head of a Neo-Druid initiatory order, is also a member of at least a dozen other "secret" societies. He has also practiced ritual magic according to the system of the Golden Dawn. Thus, Greer is probably pretty qualified to single-handedly write an encyclopaedia of this kind!
The volume covers occult orders, rituals and other practices, symbols, and personages (both human and angelic). Some entries deal with well-known subjects. Who hasn't heard of Nostradamus, Theosophy, pentagrams, Wicca or scrying? Other subjects are more obscure: the Order of Sat B'hai, Seax-Wicca, sesquiquintile, zorvoyance and Kindred of the Kibbo Kift, to mention a few! And what are we to make of the Women's International Terrorist Conspiracy from Hell (WITCH) and Taphthartharath? You heard me.
I suppose I must point out that Greer's opus isn't particularly sensationalist. There is very little information on black magic, Satanism, demons and other dark subjects often associated with occultism in the public mind. Greer is decidedly on the side of the "White Lodges". Indeed, the encyclopaedia often gets pretty boring, page after page filled with Kabbalistic sefirot and their angels, Tarot cards and astrological aspects. Some people will inevitably be disappointed that their favourite subjects are covered too briefly, too critically or not at all. Thus, the entry on Valentin Tomberg is very short, while everything Golden Dawn-related is treated at some length.
Those who want a more fun read should consult "The Element Encyclopedia of Secret Societies" instead. That book is also written by...John Michael Greer.
Finis coronat opus.