In the last three decades. use of antibiotics/drugs in animal husbandry programs has grown tremendously. Antibiotics/drugs are used therapeutically to cure diseases. and subtherapeutically to control the outbreak of diseases, improve feed efficiency and promote growth. The presence of antibiotic/drug residues in food products of animal origin. i.e ** meat, poultry and milk, can be a potential health hazard to consumers. Significant research is being done to develop new methods or to improve on existing methods to confirm and quantitatively determine the antibiotic/drug residues in meat, poultry and milk. This book covers recent development and application of various analytical techniques for the determination of antibiotic/drug residues in food products of animal origin. I thank the authors for their time and efforts in preparing the manuscripts and all the reviewers for reviewing the manuscripts. I also thank to the Division of Agricultural and Food Chemistry of the American Chemical Society for sponsoring the symposium and Hewlett Packard, Palo Alto, CA, Perkin Elmer Corp., Norwalk, CT, Millipore Corporation, Milford, MA, and Kraft General Foods, Glenview, IL, for their generous financial support for the symposium. Vipin K. Agarwal New Haven, CT v CONTENTS Importance of Laboratory Validations and Accurate Descriptions of Analytical Procedures for Drug Residues in Foods ................. .