The field of ultrafast spectroscopy of semiconductors and their nanostructures continues to be an active field of research. Exciting new developments have taken place since the first edition of this book was completed in 1995. This revised edition includes a discussion of many of these recent developments in the field. This is accomplished by adding a chapter on Recent De­ velopments at the end of the book. This approach was selected to provide a discussion of results while they are still relatively recent. Results published before the end of May 1998 were considered for inclusion in this book. The objective of this revised edition remains the same as before: to provide a co­ hesive discussion of the many diverse contributions of ultrafast spectrosco­ py to the field of semiconductors. Extensive cross-references are made to earlier chapters in order to accomplish this goal. The chapter on Recent Developments begins with a brief discussion of new lasers, new techniques of ultrafast spectroscopy and novel nanostructures. This is followed by a section on Coherent Spectroscopy where some of the most interesting recent developments have taken place. These include observation of quantum kinetic effects, effects that require going beyond the mean-field approach of the semiconductor Bloch equations, coherent control of populations and current in semiconductors, exciton-continuum interac­ tions, and many diverse aspects of coherent spectroscopy including studies of microcavities, Bragg structures, quantum dots and quantum wires.