The Physics of Plasmas provides a comprehensive introduction to the subject, illustrating the basic theory with examples drawn from fusion, space and astrophysical plasmas. Various aspects of plasma physics are discussed, beginning with particle orbit theory, and including fluid equations, a variety of magnetohydrodynamic (MHD) models, wave equations and kinetic theory. The relationships between these distinct approaches are discussed. In this way, the reader gains a firm grounding in the fundamentals, leading to an understanding of some of the more specialized topics. Throughout the text, there is an emphasis on the physical interpretation of plasma phenomena; Exercises are included.