Ultrafast spectroscopy has proven to be a versatile and powerful tool for investigating transient phenomena. This book provides fundamental principle and general experimental setup of ultrafast spectroscopy techniques, basic theory of semiconductor carrier dynamics, as well as basic concepts of semiconductor nanostructures. The detailed investigations into the electronic and optical properties of various semiconductor quantum systems are presented using a variety of ultrafast techniques, including up-conversion photoluminescence, pump-probe, photon echoes and four-wave mixing on the time...