This book is an introduction to the field of modern plasma physics theory. The topics have been carefully chosen by the authors after many years teaching a graduate course in this subject. The book contains a comprehensive description of three widely used models in plasma physics: one-particle, hydro-dynamic and kinetic. The original results concerning fluctuation theory, nonlinear wave interaction and plasma turbulence have been obtained within the framework of the kinetic approach. This volume will be of particular interest to graduate students and researchers studying plasma physics as well as statistical physics and magnetohydrodynamics. It will also be of use to students and researchers in physical astronomy, particularly in other space plasma physics such as solar physics and stellar structure. The elements of the kinetic theory of gases.