Take a look at the Rise of the Rune Lords Adventure path Anniversary Edition. Matt goes over the book and shares his findings. The anniversary edition has had a few changes, we try and discuss them without spoiling the book for you. There is just so much that can be said for this piece of history.
For more information on the Rise of the Rune Lords you can visit Paizo
Here is their video on the Collectors edition of the Anniversary Edition
Our Flip Through of the Ultimate Equipment Guide.