Nonequilibrium - hot - charge carriers play a crucial role in the physics and techlogy of semiconductor nastructure devices. This book discusses fundamental aspects of hot carriers in quasi-two-dimensional systems and the impact of these carriers on semiconductor devices. The work aims to provide scientists and engineers with a review of the most exciting recent developments in this rapidly moving field. It should be read by all those who wish to learn the fundamentals of contemporary ultra-small, ultra-fast semiconductor devices. Features and benefits include reduced dimensionality and quantum wells; carrier-phon interactions and hot phons; femtosecond optical studies of hot carriers; ballistic transport; and submicron and resonant tunneling devices.