The symposium held at Freiburg on September 10th, 1983 had been con- cerned with methodical problems in early detection. chiefly of can- cer. The first lectures dealt with mathematical models. They were followed by contributions to the possibilities of obtaining the pa- rameters required by the models and for the assessment of the me- thods. The two final lectures outlined a monitoring system for rare diseases and some problems in early detecting heart and circulation diseases. The meeting had been organized by the Deutsche Gesellschaft fUr Me- dizinische Dokumentation. Informatik und Statistik (GMDS). Thus the programme committee was set up by the heads of the GMDS Arbeitsgrup- pen affected by the respective topics. namely Dr. Keil (epidemiology}. Prof -. Dr. NeiS (statistical methods). PD Dr. Schwartz (systematic preventive checkup and early detection). PD Dr. Trampisch (methods of prognosis and decision making) and the signer. This is a welcome opportunity to put on record my thanks to various people and organizations. The lecturers had elaborated their manus- cripts and some have revised them. The individual discussions had been conducted by Prof. Dr. Dietz. Prof. Dr. Michaelis. Prof. Dr.