The NASA/University of Maryland Vegetation Canopy Lidar (VCL) mission will create the first maps of the three-dimensional structure of vegetation in the world's forests. VCL has two primary scientific goals. On the local and regional scale, VCL maps will provide new measurements of the age and condition of forest ecosystems. They will increase by 200,000 times the area of tropical land surface surveyed. On a global scale, VCL maps provide an inventory of forest biomass and new measurements of the texture of the Earth's land cover, a critical factor used in climate modeling and weather prediction.