This volume offers a broad overview of the science and technology of remote sensing, its policy implications, and the needs of operational users in the context of climate change and environmental degradation over land. The various chapters derive from presentations originally made at the first ENAMORS conference on Optical Remote Sensing of Terrestrial Surfaces: New Sensors, Advanced Algorithms, and the Opportunity for Novel Applications, held in Tuusula, Finland, in September 1997. This meeting assembled a distinguished panel of scientists, engineers, users, and policy makers, and provided a forum to debate scientific priorities, technological opportunities, and information requirements. Policy makers strive to take full advantage of investments in Earth Observation, scientists develop new and better algorithms to deliver more accurate characterizations of the environment, or propose innovative applications, while Space Agencies design observational systems better adapted to meet the requirements of a broad spectrum of scientific missions.