The Handbook of Spectroscopy is intended to serve as an authoritative reference source for a broad audience involved in the research, teaching, learning, and practice of spectroscopic technologies. Spectroscopy is defined as the science that deals with interactions between electromagnetic radiation and matter. This research field has recently experienced an explosive growth as a result of innovations in methodologies and instrumentation, which offer the possibilities for new applications and novel methods of analysis to solve common analytical problems as well as address new challenges. Research scientists, analytical scientists, environmental investigators, and industrial engineers, who are often confronted with the ever-increasing complexity of real-life sample analysis, need a readily accessible.