The 9th International Symposium on High Energy Spin Physics, held in Bonn, 6-15 September 1990, attracted 280 participants from 16 countries. This meet ing covered not only fundamental experimental and theoretical spin phenomena but also technological developments in polarized beams and targets. For the first time intermediate energy spin physics with electron machines was discussed extensively. Highlights included the work on polarized high energy electron beams at LEP and TRISTAN and the failure of the standard model in connection with spin phenomena, in particular the growth of the spin asymmetry in violent proton-proton scattering. Also the presentation of different models in con nection with the still-unsolved 'proton spin crisis' and the proposals for four different experiments to determine the spin structure functions caused lively and sometimes controversial discussions. The Organizing Committee would like to thank all speakers for their excel lent talks, the conveners for the organization of the parallel sessions, and the International Advisory Committee for their advice. Four workshops preceded the symposium. 160 participants, among them many young physicists, discussed mainly technological spin problems. These papers are published in separate proceedings. We gratefully acknowledge the enthusiastic help of the members of our institute in preparing and running the conference and the workshops, especially Mrs. D. FaSbender, Mrs. E. Wendorf, Mrs. J. Wetzel, and Dr. U.Idschok."

The 500 MeV-Elektron-Synchrotron of the Physikalisches Institut der Universitat Bonn started to operate 1958. This was the beginning of the experimental High Energy Physics in Germany. 1964 the design of a 2. 5 GeV-Elektron-Synchrotron began. The machine was completed at the end of 1966. The construction and the performance of the machine will be dis- cussed. Resume Le synchrotron a electrons de 500 MeV de l'Institut de physique de l'uni- versite de Bonn a commence a fonctionner en 1958. Ce fut le debut de la physique experimentale des hautes energies en Allemagne. En 1964 a com- mence la construction d'un synchrotron a electrons de 2,5 GeV. L'appareil a ete acheve fin 1966. L'auteur etudie la construction et le fonctionnement de la machine. Entwicklung der Hochenergiephysik in Bonn 17 Abb. 1: Teilansicht des 2,5-GeV-Elektronen-Synchrotrons. Der mittlere Durchmesser des Magnetringes betragt 22 m. (Foto: K. KuHner) 18 Karlheinz AlthoH Abb. 2: Zwischen den beiden Magnetselektoren erkennt man einen der beiden Hohlraum- resonatoren, in dem die Beschleunigung der Elektronen erfolgt. (Foto: K. KuHner) Entwicklung der Hochenergiephysik in Bonn 19 Abb. 3: Ein 25-MeV-Linearbeschleuniger dient zur Erzeugung lind Vorbeschleunigung der Elektronen. (Foto: K. KuHner) Kernstrukturuntersuchungen mit modernen Beschleunigern Von Theo Mayer-Kuckuk, Bonn Einleitung Die Kernphysik, von der in diesem Bericht die Rede sein soll, ist der altere Bruder der Elementarteilchenphysik, uber deren Instrumentarium Herr Althoff im vorangehenden Beitrag berichtet hat. Zur Abgrenzung der Gebiete sei folgendes vorausgeschickt.