This audiobook, the culmination of 40 years of theorizing about the moral status of animals, explicates and justifies society's moral obligation to animals in terms of the commonsense metaphysics and ethics of Aristotle's concept of telos. The author uses this concept to assert that humans have a responsibility to treat animals ethically. Aristotle used the concept, from the Greek word for end or purpose, as the core explanatory concept for the world we live in. We understand what an animal is by what it does. This is the nature of an animal, and helps us understand our obligations to animals.