Being a fan of everything related to hell, Asmodeus and that entire aspect of roleplaying, I simply had to get this book. And I can't say that I regret it now, on the third day since picking it up from postal delivery.
I enjoy the stories and flavour in the start and ending, the content is great and very rich on details.
The diabolist prestige class covers an area I have missed proper coverage of and has exactly the right feeling of both the great powers a pact with hell has - as well as the ultimate damnation it includes.
A great thanks for the notes on the Pathfinder version of the Archdukes as well. I am generally very happy that the take manage to have all that I loved and adored about earlier versions of hell, while still being uniquely pathfinder.
At the end of the day all I can say about this is: I wish, burningly, that there was more. And well, I must say a more detailed description of the individual layers of hell, with drawings, maps and more of the (already adorable) interesting locations would definitely be an adorable addition to this book. Especially for GM, who like me, find the urge to send the players on a visit to the plane of LE-alignment nearly irresistible (this book certainly doesn't make that urge smaller!)
... since I live in Denamrk I have the privilege of knowing this author's book very well, and while I can't say much about the english translation, I can say that if it's half as good as the original, any fantasy reader should probably find it worthwhile. It has some very interesting ideas and concepts, a well-functioning plot, and some really unexpected turns. Not to mention that for all who love the traditional idea of wizards in roleplaying games, this is probably quite the inspiration and an even greater story.
... I shall hereby finally decide that there is no such things as words to properly describe how satisfied I am with this product. I could give you a list of "I likes" but, really it would be a list of the books contents. Allthough I must say I am overly fond of the entire section about law/legal procedures and society structure in Cheliax - absolutely adorable.
I am planning to GM CoT soon and this certainly helped to convince me to do so... (now, how do I finish of Second Darkness fastly... looks at final book... hmm... doomsday effect... will do...)
Great work. Really. Great. Awesome. Worth 10 Stars... *searches for better rating*