The aim of this book is to present in an elementary manner the basic principles of modern meteorology. Intended for students without previous acquaintance with the subject, it is written in response to a demand for a nontechnical text to serve the many short and elementary courses in meteorology already in progress in the United States. It is written more for the purpose of creating interest and background than for furnishing a technical and detailed discussion of the various branches of meteorology. For this reason the use of calculus in the presentation of meteorological theories has been avoided. Actually, this book is an expansion of a chapter on meteorology written for the British Empire edition and the American edition of Weems's "Air Navigation" and an abbreviation of the author's recent book "Weather Analysis and Forecasting." However, this book is not addressed specifically to pilots or weather forecasters, although its leaning is decidedly toward synoptic and aeronautical meteorology. On account of its elementary character, the text does not contain references to meteorological journals and papers. Instead, a list of advanced textbooks is included to assist the reader in finding more advanced literature on meteorology. The author's warm thanks go to Miss Margaret Whitcomb for her valuable assistance in revising the text, preparing the diagrams and tables, proofreading, and indexing.