From the publisher's website:
Magic has suffused the Inner Sea region for thousands of years. This book takes a detailed look at the magical traditions of the Inner Sea, including rules for magic variants (from hideous fleshwarping rituals to the wild and unpredictable surges of primal magic), examinations of how magic is taught (be it in schools, temples, guilds, or secret societies), and how the spellcasters of the region have chosen to specialize in various forms of magic.
This 64-page book presents two new oracle mysteries, 18 new archetypes for spellcasting classes, a pair of prestige classes (the cypher mage and the divine scion), and a wide selection of unique, unusual, and exciting new spells for all who would seek to master the art of magic.