This book describes the basic physical images of the space environment extending from the sun to the earth as well as series of phenomena caused by its solar activities. Special emphasis is placed on how fluctuations in the space environment affect space itself and our social systems here on earth. Contents An overview of the Space Environment/The Sun and Solar Winds/The Ionosphere and Radio Wave Propagation/The Magnetosphere and Particle Activity/The Space Radiation Environment and Utilizing Cosmic Information/The Geospace Radio Environment