The NATO . Advanced Research Insti tute on Nonequilibrium Processes in Partially Ionized Gases was held at Acquafredda di Maratea during 4-17 June 1989. The Institute considered the interconnections between scattering and transport theories and modeling of nonequilibrium systems generated by electrical discharges, emphasizing the importance of microscopic processes in affecting the bulk properties of plasmas. The book tries to reproduce these lines. In particular several contributions describe scattering cross sections involving electrons interacting with atoms and molecules in both ground and excited states (from theoretical and experimental point of view), of energy transfer processes as well as reactive ones involving excited molecules colliding with atoms and molecules as well as with metallic surfaces. Other contributions deal with the basis of transport theories (Boltzmann and Monte Carlo methods) for describing the bulk properties of non equilibrium plasmas as well as with the modeling of complicated systems emphasizing in particular the strong coupling between the Boltzmann equation and excited state kinetics. Finally the book contains several contributions describing applications in different fields such as Excimer Lasers, Negative Ion Production, RF Discharges, Plasma Chemistry, Atmospheric Processes and Physics of Lamps. The Organizing Committee gratefully acknowledges the generous financial support provided by the NATO Science Committee as well as by Azienda Autonoma di Soggiorno e Turismo of Maratea, by University of Bari, by C. N. R. (Centro di Studio per la Chimica dei Plasmi and Comitato per la Chimica), by ENEA, by Lawrence Livermore Laboratory and by US Army Research Office.