This volume represents the formal presentations and discussions which took place during a three-day meeting in March 1988 at The University of Texas M. D. Anderson Cancer Center in Houston. It is" dedicated to my friend of more than thirty years, Prof. Dr. Klaus Joachim Ziilch, who died in Berlin on December 2. 1988 while this volume was still in preparation. Klaus Zulch had devoted a significant portion of his professional life to a better understanding of central nervous tumors. Over the past two decades he served as the Director of the Collaborating Center for CNS Tumors, under the...