The study of the Earth's atmosphere and the related physical processes falls under the domain of atmospheric science. It can be divided into meteorology, aeronomy and climatology. The discipline of meteorology includes atmospheric chemistry and atmospheric physics, and primarily focuses on weather forecasting. Climatology studies the changes and variations occurring in the atmosphere. Aeronomy studies the upper layers of the atmosphere with a major focus upon dissociation and ionization. Atmospheric science also includes planetary science, and the study of the atmosphere of planets and natural satellites of the solar system. This textbook is compiled in such a manner, that it will provide in-depth knowledge about the theory and practice of this field. The various sub-fields of atmospheric science along with technological progress that have future implications are glanced at in this book. It is a complete source of knowledge on the present status of this important discipline.