Ever since its establishment by USDA regulation in the mid-1980s, the Institutional Animal Care and Use Committee (IACUC) has evolved as the premier instrument of animal welfare oversight within research institutions in the United States. As biomedical research continuously grows, the role and impact of the IACUC has increased in scope and complexity. The IACUC Handbook has become "the Bible" for individuals when the time comes for them to serve on their institution's IACUC. It provides a foundation for understanding and implementing the many and varied responsibilities of this committee. This Third Edition comprehensively addresses the significant changes in the pertinent regulatory environment and interpretation of applicable federal laws, regulations, and policies. It provides multiple references and commentary on the new edition of the Guide for the Care and Use of Laboratory Animals, the new AVMA Guidelines for the Euthanasia of Animals: 2013 Edition, and the Office of Laboratory Animal Welfare's Frequently Asked Questions. The Third Edition also features an updated survey of IACUC practices from institutions around the United States, offering wisdom gained from their experience. In addition, it includes a chapter that provides an international perspective on how animal welfare reviews can function in other countries.