This book is intended for a semester undergraduate course in atmospheric thermodynamics. Writing it has been in my mind for a while. The main reason for wanting to write a book like this was that, simply, no such text in atmospheric thermodynamics exists. Do not get me wrong here. Excellent books treating the subject do exist and I have been positively influenced and guided by them in writing this one. However, in the past, atmospheric thermodynamics was either treated at graduate level or at undergraduate level in a partial way (using part of a general book in atmospheric physics) or too fully (thus making it difficult to fit it into.