I was introduced to this book by a friend who thought I might find it fascinating. He was right. this is a lost book of space/time magic. A lot of the concepts are dated and its fair to say this book is more theory than practice. In fact I wish the author had included exercises. Nonetheless if you're interested in space/time magic this book is worth picking up and reading. If nothing else it illustrates that there is more work out there to be discovered, both in term of magical work, and also in terms people who've contributed to magic as an evolving discipline.