This book introduces the principles of remote sensing from an Earth resource perspective. It describes a) the fundamental characteristics of electromagnetic radiation and how the energy interacts with Earth materials such as vegetation, water, soil and rock, b) how the energy reflected or emitted from these materials is recorded using a variety of remote sensing instruments (e.g., cameras, multispectral scanners, hyperspectral instruments, RADAR), and c) how we can extract fundamental biophysical or land use/land cover information from the remote sensor data. The history of remote sensing, the principles of visual photo-interpretation, and photogrammetry are also presented. Application chapters focus on remote sensing of vegetation, water, urban land use, and soil/rock and geomorphic features.