This proceedings volume covers new results from recent studies on impurity states, bound states in semiconductors, phonons, excitons and electron confinement in superlattices and quantum wells, magnetooptics, optical properties of solids in far infrared and millimeter wave regions, optical nonlinearity for III-V, II-VI compounds, Si, Ge, amorphous and organic semiconductors as well as optical crystals. Special emphasis is placed on the 2DEG system.