Hormonal Proteins and Peptides: β-Endorphin, Volume X focuses on the chemistry, biology, and clinical investigations of opioid peptides. This book discusses the chemical approach in isolating a chemical entity from its natural source and investigates its biological activity after it has been determined to be a pure substance. Organized into nine chapters, this volume starts with an overview of the structure–activity relationship of β-endorphin (β-EP) by synthetic approach. This text then explores the proteinases involved in the generation of opioid peptides, including β-EP from β-lipotropin (β-LPH). Other chapters review the biosynthesis of β-EP and consider in detail the opiate receptor. This book discusses as well the anatomy of β-EP-containing structures in pituitary and brain. The final chapter presents a discussion on the historical aspects of opiate–peptide discoveries, particularly in the field of narcotic antagonists. This book is a valuable resource for chemists, biologists, endocrinologists, physicians, and neurobiologists.