Book excerpt: Introduction to Nonlinear Laser Spectroscopy focuses on the principles of nonlinear laser spectroscopy. This book discusses the experimental techniques of nonlinear optics and spectroscopy. Comprised of seven chapters, this book starts with an overview of the stimulated Raman effect and coherent anti-Stokes Raman spectroscopy, which can be used in a varied way to generate radiation in the ultraviolet and vacuum-ultraviolet areas. This text then explains the simplest quantum-mechanical system consisting of an isolated entity with energy eigenstates