The 9th International Symposium on High Energy Spin Physics was held in Bonn, 6-15 September 1990, with the Physikalisches Institut der Universitat Bonn as the host. The symposium was preceded by a series of four workshops on • polarized electron sources and electron spin polarimeters • Siberian snakes and polarization in circular machines • polarized gas targets • polarized solid targets. 160 participants from 11 countries, among them many young physicists, came together and discussed mainly technological spin problems. The high level of participation indicates that workshops combined with the symposium are attractive not only for people who plan and prepare polarized beams and targets but also for experimentalists and theorists dealing with high energy spin physics. At these workshops many very interesting and important recent results were presented and reviewed. Thus we hope these proceedings will be valuable to many researchers in these fields. The Organizing Committee would like to thank all participants, in particular the speakers and the session chairmen, for their contributions to the workshops and for helping to create a lively and stimulating atmosphere. Special thanks go to the organizers - W. Haeberli, S. Mango, E. Reichert, E. Steffens, W. Thiel, U. Wienands - for their cooperation in preparing and running these workshops. 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 9th International Symposium on High Energy Spin Physics was held in Bonn, 6-15 September 1990, with the Physikalisches Institut der Universitat Bonn as the host. The symposium was preceded by a series of four workshops on • polarized electron sources and electron spin polarimeters • Siberian snakes and polarization in circular machines • polarized gas targets • polarized solid targets. 160 participants from 11 countries, among them many young physicists, came together and discussed mainly technological spin problems. The high level of participation indicates that workshops combined with the symposium are attractive not only for people who plan and prepare polarized beams and targets but also for experimentalists and theorists dealing with high energy spin physics. At these workshops many very interesting and important recent results were presented and reviewed. Thus we hope these proceedings will be valuable to many researchers in these fields. The Organizing Committee would like to thank all participants, in particular the speakers and the session chairmen, for their contributions to the workshops and for helping to create a lively and stimulating atmosphere. Special thanks go to the organizers - W. Haeberli, S. Mango, E. Reichert, E. Steffens, W. Thiel, U. Wienands - for their cooperation in preparing and running these workshops. 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 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 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.

For Thomas Putze, performance is a snapshot of a moment, a play on possibilities, and at the same time a well-planned and sophisticated act to captivate the onlooker. Yet above all, it is thinking, drawing, sculpting, and realising with and through the body, which he treats just as relentlessly as all the other materials in his works. He swings through trees, occupies church facades, and submerges himself in mud; frequently without clothing or scantily wrapped in plastic sheeting, he gauges and challenges the physical and thus social space between us bystanders. Thomas Putze typifies the risk of being human, with all its failings and plenty of humour. He not only holds us to account but rather invites us to do this ourselves: to partake in art and to reflect on the performance we call life.Text in English and German.

The 9th International Symposium on High Energy Spin Physics was held in Bonn, 6-15 September 1990, with the Physikalisches Institut der Universitat Bonn as the host. The symposium was preceded by a series of four workshops on • polarized electron sources and electron spin polarimeters • Siberian snakes and polarization in circular machines • polarized gas targets • polarized solid targets. 160 participants from 11 countries, among them many young physicists, came together and discussed mainly technological spin problems. The high level of participation indicates that workshops combined with the symposium are attractive not only for people who plan and prepare polarized beams and targets but also for experimentalists and theorists dealing with high energy spin physics. At these workshops many very interesting and important recent results were presented and reviewed. Thus we hope these proceedings will be valuable to many researchers in these fields. The Organizing Committee would like to thank all participants, in particular the speakers and the session chairmen, for their contributions to the workshops and for helping to create a lively and stimulating atmosphere. Special thanks go to the organizers - W. Haeberli, S. Mango, E. Reichert, E. Steffens, W. Thiel, U. Wienands - for their cooperation in preparing and running these workshops. 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 9th International Symposium on High Energy Spin Physics was held in Bonn, 6-15 September 1990, with the Physikalisches Institut der Universitat Bonn as the host. The symposium was preceded by a series of four workshops on • polarized electron sources and electron spin polarimeters • Siberian snakes and polarization in circular machines • polarized gas targets • polarized solid targets. 160 participants from 11 countries, among them many young physicists, came together and discussed mainly technological spin problems. The high level of participation indicates that workshops combined with the symposium are attractive not only for people who plan and prepare polarized beams and targets but also for experimentalists and theorists dealing with high energy spin physics. At these workshops many very interesting and important recent results were presented and reviewed. Thus we hope these proceedings will be valuable to many researchers in these fields. The Organizing Committee would like to thank all participants, in particular the speakers and the session chairmen, for their contributions to the workshops and for helping to create a lively and stimulating atmosphere. Special thanks go to the organizers - W. Haeberli, S. Mango, E. Reichert, E. Steffens, W. Thiel, U. Wienands - for their cooperation in preparing and running these workshops. 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 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 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.

For Thomas Putze, performance is a snapshot of a moment, a play on possibilities, and at the same time a well-planned and sophisticated act to captivate the onlooker. Yet above all, it is thinking, drawing, sculpting, and realising with and through the body, which he treats just as relentlessly as all the other materials in his works. He swings through trees, occupies church facades, and submerges himself in mud; frequently without clothing or scantily wrapped in plastic sheeting, he gauges and challenges the physical and thus social space between us bystanders. Thomas Putze typifies the risk of being human, with all its failings and plenty of humour. He not only holds us to account but rather invites us to do this ourselves: to partake in art and to reflect on the performance we call life.Text in English and German.