This book represents the most comprehensive description of the physical foundations of methods and instruments in the fields of passive remote sensing applied to investigations of the Earth, Solar system bodies and space. Emphasis is placed on the physical aspects necessary to judge the possibilities and limitations of passive remote sensing methods in specific observation cases. Numerous practical applications and illustrations are given referring to airspace up-to-date experiments. Due to the lack in traditional separation on methods and instruments of remote sensing of the Earth and outerterrestrial space this book aims to supply more information in this field.