Israel Regardie 
Ceremonial Magic [PDF ebook] 
A Guide to the Mechanisms of Ritual

The proper working of ritual is at the heart of the Western magical tradition. This book shows exactly how ceremonial techniques can be used to concentrate and harness the enormous psychic and spiritual potential of human consciousness. Dr Regardie’s detailed analysis and description of key rituals are based on his own considerable experience and his knowledge of Golden Dawn techniques. In addition to providing practical instructions on robes, ritual equipment and decor, he also links current occult practice to broader historical precedents.