When this book was first published in 1984, the technique of remote sounding was growing rapidly in importance as a means for studying the structure, climate and weather of the atmospheres of the Earth and planets. Measurements from Earth satellites and interplanetary spacecraft proved particularly useful because they allowed good coverage of atmospheric systems in space and time, often with high resolution. This book describes how measurements can be made of the properties of the Earth and planets using this method. It includes descriptions of the scientific principles, technical implementation, mathematical methods for analysing the measurements, a history of measurements that have been made and discussions of the phenomena that have been discovered and studied using remote sounding. The technique is important for meteorology, climatology and an understanding of humankind's impact on the Earth's atmosphere.