Book excerpt: Vesuvius, Campi Flegrei, and Campanian Volcanism communicates the state-of-the-art scientific knowledge on past and active volcanism in an area characterized by elevated risk due to high-density population. Eruptions, lahars and poisonous gas clouds have killed many thousands of people over recorded history, but volcanoes have given people some of the most fertile soil known in agriculture. The research presented in this book is useful for policymakers and researchers from these and other countries who are looking for risk assessment and volcanic evolution models they can apply to similar situations around the world. Naples and its surrounding area, in particular, the area situated between Vesuvius and the Campi Flegrei volcanic area has a population in excess of 4 million people. The volcanic areas that have similarly large populations in proximity to dormant, but hazardous volcanoes, i.e., Indonesia and Central America can also benefit from this work. Covers the fundamental science of volcanoes, including new developments in the last decade relating to the use of crystals and melt inclusions to model the nature and evolution of volatiles Includes the latest research on volcanism in Southern Italy that is presented as a case study for active and inactive volcanoes across the globe Presents research that is applicable around the world, for people, scientists and policymakers living on, or near, active volcanoes