This book introduces the basic theoretical concepts required for the analysis of the optical response of semiconductor systems in the coherent regime. The entire presentation is based on a one-dimensional tight-binding model. Starting with discrete-level systems, increasing complexity is added gradually to the model by including band-structure and many-particle interaction. Various linear and nonlinear optical spectra and temporal phenomena are studied. The analysis of many-body effects in nonlinear optical phenomena covers a major part of the book. Only basic knowledge of quantum mechanics is required to benefit from the results presented in this book. Therefore, it is well suited as a textbook for advanced classes, for self-study, and for researchers interested in the field of semiconductor optics.