Earth science is evolving into Earth system science,changing from a discipline-specific premise to aninterdisciplinary endeavor. Increased awareness of humandependence and impact upon the environment has made globalchange research one of the most pressing policy issuesfacing decision makers today. This book presents an overview of past, present, and futuresatellite missions and programs and their sensorcomplements. An effort has been made to show to some extentthe scale and nature of existingnational and internationalactivities and operations in this context. Text andillustrations are intended as a guide and roadmap toeveryone interested in the wide field of Earth observation. In particular, the book may serve as a reference, or givereasonable inputs, on the following subjects: Programmaticplanning on all levels, planning for the requiredinfrastructure, exisiting and planned operational serviceprovision, data utilization and exploitation.