This field guide covers a broad spectrum of topics in the field of spectroscopy, condensing the subjects to their essentials. As such, novices can use this guide to obtain an overview of the field, and experts can use it as a quick reference. Beginning with basic definitions and explanations, this guide then describes the instruments that are used in the field - from filters, lenses, mirrors, and modulators, to monochromators, interferometers, and detectors. A third section outlines theory and methods as they relate to spectroscopy: the Fourier transform, quantum mechanics, approximation methods, nuclear magnetic resonance, and more. Additional features include a glossary of variables and symbols, and an equation summary.