Book excerpt: The first comprehensive book to cover all aspects of the last 25 years of PACAP (pituitary adenylate cyclase activating polypeptide) research, this book contains contributions from virtually all the leading researchers in the field, and addresses some of the following topics: evolutionary aspects of PACAP, distribution and occurrence of PACAP and its receptors, hormonal effects of PACAP, intracellular signaling, effects on cellular proliferation and differentiation, protective effects of PACAP, behavioral effects of PACAP, developmental aspects of PACAP, other physiological effects of PACAP (cardiovascular, thermoregulatory), human studies, drug design, metabolism and transport. This compendium can serve as an important reference for researchers and students in PACAP research and can also be a thorough introduction for those in related fields.