Several of the greatest disasters in history were caused by volcanic eruptions, and some have influenced the course of human civilization. Inevitably, the sheer physical power of volcanic eruptions makes them of compelling interest. Apart from their immediate effects, large eruptions also have world-wide atmospheric effects, with implications for the global climate that are becoming of increasing current concern. In this book, Dr Francis gives an account - much of it from first-hand experience in many parts of the world - of the familiar violent aspects of volcanoes and the various forms that eruptions can take. He also goes beyond the spectacular visible displays to explore why volcanoes occur where they do, and how examples of major historical eruptions can be interpreted in terms of physical processes. Throughout he attempts to place volcanism in a planetary perspective, exploring the preeminent role of submarine volcanism on Earth and the stunning range of volcanic phenomena revealed by spacecraft exploration of the Solar System. This book is intended for students of geology, geography, and environmental science (first-year and above); those teaching these subjects; amateur geologists.