These volumes present the Proceedings of the "Third Interna tional Workshop on Solar Thermal Central Receiver Systems" or ganized by the DFVLR and held in Konstanz, Federal Republic of Germany, June, 1986. The Workshop was the continuation of the conferences in Claremont, USA, 1982 and in Varese, Italy, 1984 on the subject of "Central Receiver Projects" and of the con ferences in Stuttgart, Federal Republic of Germany, 1983 and in Atlanta, USA, 1985 on the subject of "High Temperature Solar Technology and Application". The success of the Workshop was indicated by the participation of 113 scientists from 11 nations. The Workshop was mainly ad dressed to persons actively working in the field of "Solarthermal". But also participants from neighboring areas of investigation were welcomed, e.g. those from Photovoltaics who deal with temperature effects. Several small Solar Thermal Power Plants have been successfully operated in recent years; their results enable the scientific and technical community to judge on technical viabilities, as sess operational characteristics, and evaluate and extrapolate thermal and electrical performances. Summarizing and comparing these experiences was the topic of the first part of the Work shop which dealt with "Plants".