From the introduction:
This book is about shapeshifters that combine elements of humanoid and animal. Striving to avoid serving any great power, animal lords focus on themselves and on day-to-day survival. Their powers are innate, or the result of pacts with lesser spirits as equals, not as patron and supplicant. The shape changers in this book all have a magical relationship to one family of animals, such as felines, canines, or even dinosaurs. Taking on more and more of the shape and abilities of their totem animal.
Included within is a new heroic class the animal lord, an animal lord archetype, and one barbarian archetypes, the serker and the were lord. All are close to the primal forces of nature, the barbarians wrestling with nature to take this power to use in their rage, while the animal lord seeks unity with his animal family and assumes actual lordship of his animal kin. All follow statistics of animal families, outlining the abilities offered by 21 different families of animals. Finally, there is a small bestiary of animals whose forms can be assumed.