Ionospheres provides a comprehensive description of the physical, plasma and chemical processes controlling the behavior of ionospheres. The relevant transport equations and related coefficients are derived in detail and their applicability and limitations are described. Relevant wave processes are outlined and important ion chemical processes and reaction rates are presented. The various energy deposition and transfer mechanisms are described in some detail, and a chapter is devoted to the various processes controlling the upper atmosphere and exosphere. The second half of the book presents our current understanding of the structure, chemistry, dynamics and energetics of the terrestrial ionosphere, and other solar system bodies. The final chapter describes ionospheric measurement techniques. The book will form a comprehensive and lasting reference for scientists interested in ionospheres, and it will also prove an ideal textbook for graduate students. It contains extensive student problem sets, and an answer book is available for instructors.