Every year as many as six million companion animals are euthanized for behavior problems in the United States alone. Every day veterinarians in practice are asked to treat pets exhibiting problem behaviors - behaviors that often can't be treated by traditional behavior modification therapy alone. In the last several years, pharmacologic treatments of behavior have made significant advances and can serve as a critical part of therapy. For students and professionals in veterinary medicine and animal science Veterinary Pscyhopharmacology is the only complete source of current knowledge on the subject of pharmacologic behavior modification. Classification of disorders is eschewed in favor of in-depth explanations of pharmacologic options in inducing behavior changes. Special emphasis is given to explaining the underlying mechanism of pharmacologic agents used in therapy; thus, veterinarians will know not only which drugs to prescribe but why they should be prescribed and how they work.