From publisher blurb:
The Advanced Bestiary was one of the classic books of the d20 era and now it’s back for the Pathfinder RPG! The revised and expanded book features over 100 templates, a sample creature for each one, and brand new color art throughout. With concepts ranging from the fearsome blood knight to the bizarre id ooze, the Advanced Bestiary offers unprecedented flexibility for campaigns of any style. These templates can be combined with monsters from any other source to create an endless variety of new creatures, making every monster book you already own more valuable. The Advanced Bestiary: it’s not just a monster book, it’s a force multiplier!