It is within the means of many nations to conduct or participate in cost-effective Earth observation missions. This study provides a definition of cost-effective Earth observation missions and information about background material and organizational support. It discusses cost drivers and provides advice on achieving cost-effective missions and discusses training and education. The conclusions and recommendations range from more general factors, which drive the small satellite mission activities, to visions of future cost-effective Earth observation missions. Complementary to large complex missions, small satellite missions have specific advantages: more frequent missions opportunities and therefore faster return of science and application data, a larger variety of missions and greater diversification of potential users; more rapid expansion of the technical and/or scientific knowledge base; greater involvement of local and small industry. This volume will prove to be a useful source of information to governments, space agencies, academia, and industry.