The RADARSAT-2 mission comprises the construction, launch, and operation of Canada's second synthetic aperture radar earth observation spacecraft and the establishment of ground infrastructure to support the spacecraft and the data users. The RADARSAT-2 mission is being implemented in a partnership arrangement between government and private industry and will be operated and commercialized by industry. This paper provides an introduction to RADARSAT-2 and the overall context for the mission, including the background, an overview of the major operating parameters, and a description of the major elements and events in the mission. Other papers in this special issue provide details on the design of the spacecraft, the ground segment, applications, and other aspects.