The Neurosurgeons of Berlin are happy to welcome their colleagues from Germany and from foreign countries to our Annual Meeting, being held in this city once again after many years. The external appearance of the city may have changed in many respects since our winter meeting in 1965. This ist not the case, however, as concerns the outstanding quality of its cultural life. We hope that you take as much profit of it as possible. When choosing the scientific themes of this congress, we were led by the idea that problems should be discussed which are not dealt with at special symposia this year. Thus, the problems related to lumbar disc surgery and its complications were chosen as one main topic. This important chapter of neurosurgery worries (and not seldom depresses) us in our daily work. A joint statistic analysis has been made, for which we are indebted to the colleagues from the following university clinics: Essen, Freiburg, Graz, Hannover, Heidelberg, Kiel, Koln, Mainz, Wiirzburg, Berlin-Charlottenburg, Berlin Steglitz, of the Neurosurgical Department of the BG-U nfallklinik Frankfurt/Main, of the Neurosurgical Department Wagner-J auregg-Krankenhaus Linz, of the Neurosurgical Clinic of the Katharinen-Hospital Stuttgart, and of the Neurosurgical Clinic of the Stadt. Krankenhaus Berlin-N eukolln."