ESRI (Letter of Support D) is a major developer and supplier of software for spatial data handling, particularly geographic information systems (GIS), and of spatial databases. ESRI is already a participant in Alexandria, in the development of the rapid prototype. ESRI will participate in the project and make substantial contributions to cost sharing by supplying software licenses, maintenance, and training; by contributing staff time to the design and evaluation effort; by making use of its extensive customer base as a potential source of data sets and test sites; and through its growing role as a publisher and disseminator of geographic data sets.