The International Symposium on Positron Emission Tomography of the Brain was held at Schloss Auel in Lohmar, near Cologne, FRG, on May 3rd to 8th, 1982. This isolated place was chosen to bring together and keep together people active in research employing PET. The partic ipants were asked to report their ongoing work, to discuss upcoming problems, and to indicate future developments. In contrast to the large international meetings which suffer from lack of time for discussion and are affected by the distractions of major cities, our symposium provided ample opportunity for discussion during the scientific sessions and guaranteed a free exchange of ideas during the leisure time spent to gether. It also gave us the chance to celebrate the founding of a new Max Planck Institute for Neurological Research, whose two depart ments are headed by Dr. K. -A. Hossmann and myself, and to mark the start of positron emission tomography in our laboratory. The book contains the invited papers presented at the meeting and the formal minipapers given at the final general discussion, moderated su perbly by Dr. L. Sokoloff. In order to accelerate publication, the discus sions of the individual papers and the final discussion have been omit ted. However, every participant will remember the atmosphere and the highlights of the discussions, which gave a special character to the whole event."