The book opens with an explanation of what gets a Mage labeled as Left-Handed and also offers some new tricks for Apostates.
The second section details the Mad (those whose Wisdom drops to 0) and the effect they have on the Fallen World as well as rules for creating and running such characters.
The third section looks at the Scelesti, the Abyss, and Mages who follow even darker creatures. I felt this section was the weakest but not a waste of space.
My biggest draw to this book was the new information on the Tremere (the fourth and final section) and this book delivers. The Legacy gets an expanded origin story and its organization gets broken down and explained.
My biggest complaint was that the book was so short. The information about Apostates, while good, didn't feel like it belonged with the rest of the material. The Tremere were given enough depth to require their own Order book but everything was so compacted I felt like I was reading the Introduction to a much larger book. The same can be said for the Scelesti (perhaps another Night Horrors: the Unbidden needs to be written to cover that aspect).
[5 of 5 Stars!]