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....