Includes bibliographic references. Documents in English and/or French. Also issued as a supplement to: La terre et la vie, 1959. According to the list of publications from IUCN Technical Meetings, v.3 was to be published as "Natural aquatic resources" and v.4 was to be entitled "Rates of run-off and evaporation". However, "Natural aquatic resources" was issued as v.4. V.3 appears not to have been issued