Ladislaus RYBACH is professor emeritus of geophysics at the Swiss Federal Institute of Technology Zurich and managing director of GEOWATT AG in Zurich. He is president of the International Geothermal Association (IGA) and vice-chairman of the International Energy Association’s Geothermal Implementing Agreement Executive Committee. Dr. Rybach was the organizing committee chairman of the World Geothermal Congress 2000 in Japan and honorary chairman of the European Geothermal Conference 2003 in Szeged, Hungary. He is also member of the Commission on Mineral and Thermal Waters of the International Association of Hydrologists. His research activities cover a wide range, from heat flow studies and lithospheric geothermics over low-enthalpy utilization (geothermal heat pumps) to hot dry rock modeling. Dr. Rybach has published a wide variety of papers and several textbooks on general and applied geothermics and has held teaching positions at the International Geothermal Schools in Pisa, Italy and Reykjavik, Iceland and also at the Geothermal Institute of the University of Auckland in New Zealand.