Deep Magic by Kobold Press is an amazing product. Gathered within the pages of this tome are spells, archetypes and options that all bring something flavourful and new to the table. This is a book for GMs and players alike, and I can't stress enough just how amazing this book is.

The content in Deep Magic has a very high level of quality, and presents players and GMs with the most important thing in a roleplaying game: Options. There are 30 new magic "systems," flavourful options of themed magic which can be used to distinguish the magic of different casters for characters and even whole campaign settings. The hundreds of new spells are all excellent, and follow the themes presented earlier in the book to add character and style and allow unique concepts like Blood Magic, Clockwork Magic and the primal and mysterious Vril Magic. There are archetypes useful for making unique spellcasters, rules for glyph magic using runes and symbols to produce magical effects and even some much needed material expanding the official WOrds of Power system option published by Paizo in Ultimate Magic, a system Paizo themselves seem to have abandoned.

If you love magic in Pathfinder, you will fall in love with Deep Magic. It's an excellent book, and it's options will enrich any game that uses them.