The study of the interaction between matter and electromagnetic radiation as a function of the wavelength or frequency of the radiation is known as spectroscopy. It focuses on the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum. It is also involved in the study of the wavelength dependence of the absorption by a gas-phase matter of visible light dispersed by a prism. Spectroscopy is a fundamental exploratory tool in the fields of physics, chemistry, and astronomy within the electromagnetic spectrum. Some of the important applications that arise from biomedical spectroscopy are in the areas of tissue analysis and medical imaging. This book outlines the processes and applications of spectroscopy in detail. It will also provide interesting topics for research which interested readers can take up. As this field is emerging at a rapid pace, the contents of this book will help the readers understand the modern concepts and applications of the subject.