The applications of nonlinear ultrafast spectroscopy are numerous and widespread, and it is an indispensable technique in modern research. Unfortunately, it is also a topic that can be daunting to those meeting it for the first time. Making use of many worked examples and accompanied by MATLAB® codes for numerical simulations of spectra, the authors deliver a practical and intuitive approach to the subject. Assuming just an understanding of quantum mechanics and statistical mechanics, the book delivers an introduction to the subject for advanced students and researchers. It will also be useful for practitioners, who are already familiar with the subject, but who want to develop a more conceptual understanding. Once a reader has assimilated the material in this text, they will be fully equipped with the tools to devise well reasoned spectroscopic experiments.