It was a more enjoyable read than both Dead Names and Gates of the Necronomicon for me. Simon gives alot of info about the Catholic Church and is well researched. He also gives excellent advice regading invocations.

It appears that this book was originally intended to be a fairly straight translation of the 1670 edition of the Grimoire of Honorius. This section seems to be fairly accurate, though someone better at French than I should look over it.

The remainder of the book appears to have been poorly researched and quickly dashed off. The basic point about the use of magic by Catholic clergy is well-established, but Simon seems not to be familiar with such fundamental works as [[ASIN:0521785766 Magic in the Middle Ages (Canto)]] or [[ASIN:0271017511 Forbidden Rites: A Necromancer's Manual of the Fifteenth Century (Magic in History)]]. To fill out even the small number of pages allotted here, Simon must conflate legends about Catholic magicians, politically-motivated sorcery prosecutions, and cases where the practice of magic can actually be demonstrated. He very clearly wants to date the Grimoire to the same period as its supposed papal author, even though it contains material that obviously originates from centuries later.

If you want to see the Grimoire of Honorius, this will serve as a cheap translation. If you want to know about magic in the Catholic Church in the Middle Ages, the first book mentioned above will be more to your tastes.