This textbook presents a uniquely integrated approach in linking both physics and chemistry to the study of atmospheric thermodynamics. The book explains the classical laws of thermodynamics, focuses on various fluid systems, and, recognising the increasing importance of chemistry in the meteorological and climate sciences, devotes a chapter to chemical thermodynamics which includes an overview of photochemistry. Although students are expected to have some background knowledge of calculus, general chemistry and classical physics, the book provides set-aside refresher boxes as useful reminders. It contains over 100 diagrams and graphs to supplement the discussions, and a similar number of worked examples and exercises, with solutions included at the end of the book. It is ideal for a single-semester advanced course on atmospheric thermodynamics, and will prepare students for higher-level synoptic and dynamics courses.