William G. Gray, better known to many as Bill Gray, was an English ceremonial magician, Hermetic Qabalist and writer, who published widely on the subject of western esotericism and the occult. Gray founded a magical order known as the Sangreal Sodality.
Librarian note: There is more than one author in the GoodReads database with this name
This is one of Gray's most intriguing books, wherein he lays down a lot of ideas about magic, introduces you to some amazing techniques and shows you what it is like to truly live your magic. It's a work of genius and if you're serious about your magic, you should read this book. Multiple times. It'll challenge you and help you grow in your spiritual practice.
I found this amongst a whole stash of mysticism books at Goodwill. I figured the previous owner either chose a different path, or else they achieved enlightenment and didn't need the manuals anymore. Magic(k) has always seemed too D&D to me, but this book looks like it puts things in pretty reasonable terms and makes sense.