Here is an introductory examination of electromagnetic radiation. This book deals with the radiation laws, the phenomenon of radiation exchange, the quantification of radiation, and the mechanisms whereby radiation is attenuated in passing through the Earth's atmosphere. It can be used as a supplement to an introductory physics or astronomy text and also as a guide for members of the infrared community who would like additional insight into the area of radiation exchange. The concepts discussed here are well within the grasp of undergraduate students.**After studying this book, the reader will have developed a clear understanding of the phenomenon of radiatin exchange and will appreciate more thoroughly its importance in nature and its numerous applications.