I am an advanced student of astrology of many years who does readings. Astrology is my avocation. I find progressions to be a very necessary technique to factor into other timing techniques, most especially since I follow the rule of 3 - if it isn't showing up 3 times, the client is probably not going to experience it. This book is advanced technique and not for a beginning or perhaps even intermediate astrology student. There are other books that may be more introductory. I have found it to be very useful in that in clarifies some questions I had and I recommend it for that reason. I only use secondary progressions and now understand how they fit into transits and the natal much better having read this book.