This book will provide scientists, engineers and researchers with in-depth knowledge about the subject of spectroscopy. This book contains chapters describing concepts of spectroscopy, and also the applications with some practical examples. A group of international authors have presented advanced and up-to-date concepts of different types of spectroscopy in this book. To support the concepts, many practical examples have been presented in this book. Some of the chapters will help researchers in developing innovative ideas for their future projects.