Arie S. Issar is an emeritus professor at the J. Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Israel. He is currently investigating the impact of climatic changes on the hydrological cycle in collaboration with the Division of Water Sciences of UNESCO. Issar's address: The J. Blaustein Institute for Desert Research, Sede Boker Campus, 84990, Israel. Internet: issar@bgumail.bgu.ac.il