This is to Chronicles of Darkness what the Sorcerer books are to World of Darkness.

The first chapter of this book gives a large number of supernatural merits and special options for activating supernatural merits. This provides a plethora of options to mortal characters, from talking to animals to ripping out people's souls and storing them in jars. I think supernatural merits are a wonderful way to allow some oddness into the various gamelines while ensuring that the splats don't get too powerful with abilities they were never expected to have.

The second chapter dives into psychics and thaumaturges. Both of these are merit templates that feel very different from one another despite serving a primary purpose of supporting other supernatural merits. If you want a vodoun or a wiccan to have actual working magic, and you don't want to have to dive into Mage then this book has your back. Both psychic and thaumaturge have their own bundle of supernatural merits to support your other merits, or to just let you do other awesome things.

The third chapter is centered around things that should not be (aka. Cthulhu and friends). There are rules for creating things that should not be, which are ephemeral beings but with some extra powerful options (ie. influence: matter). There's also rules for using the horror system to create manifested horrors. And what would beings like that be without cultists, who have special merits and blasphemous rites. The chapter ends with a couple example things that should not be and one of their cults.

Overall if you like supernatural merits this book is a must have, if you want magic in your world and don't want to have every spell slinger be a mage, this book is a must have.