This book introduces the fundamental principles of remote sensing from an earth resource perspective. It reviews the nature of electromagnetic radiation and how the reflected or emitted energy in the visible, near-infrared, middle-infrared, thermal infrared, and microwave portions of the spectrum can be collected by a variety of sensor systems and analyzed. Emphasis in this book is placed on manual, visual image analysis of the remote sensor data using introductory photogrammetric techniques. This book is a companion volume to Dr. Jensen's widely-adopted Introductory Digital Image Processing (Prentice-Hall, Inc., 2nd Edition, 1996).