The Symposium on the Design of Water Resources Projects with Inadequate Data drew 300 participants, representing more than 60 countries. The symposium was planned within the framework of the International Hydrological Decade and was convened by Unesco and WMO. Organization of the symposium was carried out by Unesco and the Spanish National Committee for the IHD in cooperation with WMO and the IAHS. These organizations are to be commended for their efforts toward ensuring the success of the symposium. The efforts of the Spanish National Committee, which handled the many local arrangements, are especially appreciated.