Millions of people live with cats, dogs, and other pets, which they treat as members of their families. But through their daily behavior, people who love those pets, and greatly care about their welfare, help ensure short and painful lives for millions, even billions of animals that cannot easily be distinguished from dogs and cats. Today, the overwhelming percentage of animals with whom Westerners interact are raised for food. Countless animals endure lives of relentless misery and die often torturous deaths. The use of animals by human beings, often for important human purposes, has forced uncomfortable questions to center stage; Should people change their behavior? Should the law promote animal welfare? Should animals have legal rights? Should animals continue to be counted as "property"? What reforms make sense? Cass Sunstein and Martha Nussbaum bring together an all-star cast of contributors to explore the legal and political issues that underlie the campaign for animal rights and the opposition to it. Addressing ethical questions about ownership, protection against unjustified suffering, and the ability of animals to make their own choices free from human control, the authors offer numerous different perspectives on animal rights and animal welfare. They show that whatever one's ultimate conclusions, the relationship between human beings and nonhuman animals is being fundamentally rethought. This book offers a state-of-the-art treatment of that rethinking.