Book excerpt: In this volume of papers research findings on vasoactive intestinal peptide (VIP), pituitary adenylate cyclase activating peptide (PACAP), and related peptides are presented. The authors provide information on the biology, biochemistry, molecular biology, physiology, signal transduction mechanisms, and pharmacology of these peptides. Their roles in neurobiology, cell proliferation and tumorogenesis, inflammation and tissue injury, endocrinology, gastrointestinal function, and other topics are discussed, along with clinical and potential therapeutic implications.