Book excerpt: This book introduces the basic theoretical concepts required for the analysis of the optical response of semiconductor systems in the coherent regime. It is the most instructive textbook on the theory and optical effects of semiconductors. 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.