The formation of stationary high-field domains adjacent to cathode or anode, dependent on the contact potential of the electrodes, their widening with increased applied voltage and their transition into two types of moving domains are discussed. Domains which move under deformation oft he domain profilea nd usually dissolve before they reacht he anode, and nearly undeformed moving domains are described. The structure and kinetics of these domains are directly observed using the Franz-Keldysh effect and photographs of typical domain forms are presented.