Volcanology is the discipline of geologic sciences that studies volcanoes, lava, magma and the different aspects of volcanic eruptions. A volcanic eruption is a geological, geophysical and geochemical phenomenon where molten rock, known as magma, erupts onto the surface of the Earth. This phenomenon is known as volcanism. Besides the Earth, other solid-surface planets and satellites also exhibit volcanism. Geologists who study the eruptive activity and formation of volcanoes are called volcanologists. The study of current and historic eruptions of volcanoes is also undertaken within this field. Volcanologists frequently visit volcanoes to observe volcanic eruptions and collect eruptive products. One major focus of this discipline is to predict eruptions, which could save many lives during the event of a volcanic eruption. The objective of this book is to give a general view of the different areas of volcanology, and its applications. It explores all the important aspects of this field in the present day scenario. The contents of this book will help the readers understand the modern concepts and applications of the subject.