The best developed of today's kinetic theories are those for gases and completely ionized plasmas. In recent years, however, kinetic theories of more complicated systems - consisting of free particles as well as those bound in atoms, and an electromagnetic field - have played an increasingly important role. An example of such a system is a partially ionized plasma of gas discharges or in semicon­ ductors. The main purpose of this book is the further development of the kinetic theory of systems of this kind. Naturally, it would be impossible to encompass at once all the problems con­ cerning the kinetic theory of these extremely complicated systems. This book is mainly concerned with processes dominated by weak but collective interactions of charged particles and atoms, as well as processes determined by the interaction with an electromagnetic field. These topics determined the method adopted here for constructing the kinetic equations of the distribution functions for free and bound charged particles. The results of contemporary scattering theory make it possible to take strong interactions, which are interpreted as collisions, into account without any basic difficulties. More complicated, however, is the task of taking both strong interactions at small distances and weak but collective interac­ tions into account simultaneously. The solution of this problem would open an approach to a number of fundamental questions, one of which is the construc­ tion of a kinetic theory of nonideal chemically reacting systems of charged particles.