Volumes 30 and 31 of this series, dealing with "Many Degrees of
Freedom," contain the proceedings of the 1976 International Summer
Institute of Theoretical Physics, held at the university of Bielefeld
from August 23 to September 4, 1976. This institute was the eighth in a
series of summer schools devoted to particle physics and organized by
universities and research institutes in the Federal Republic of Germany.
Many degrees of freedom and collective phenomena play a critical role in
the description and understanding of elementary particles. The lectures
in this volume were intended to display how these structures occur in
various recent developments of mathematical physics. Lectures ranged
from classical nonlinear field theory over classical soliton models,
constructive quantum field theory with soliton solutions and gauge
models to the recent unified description of renormalization group tech-
niques in probabilistic language and to quantum statisti- cal dynamics
in terms of derivations. The Institute took place at the Center for
Inter- disciplinary Research of the University of Bielefeld. On behalf
of all participants, it is a pleasure to thank the officials and the
administration of the Center for their cooperation and help before and
during the Insti- tute. Special thanks go to V.C. Fulland, M. Kamper,
and A. Kottenkamp for their rapid and competent preparation of the
manuscripts.