This book is based on the pioneering work of (in chronological order) R. C. James, S. Kwapień, B. Maurey, G. Pisier, D. L. Burkholder and J. Bourgain.
We have done our best to unify and simplify the material. All participants of the Jenaer Seminar ‘Operatorenideale’ contributed their ideas and their patience. Above all, we are indebted to A. Hinrichs who made several significant improvements. From S. Geiss we learnt many results and techniques related to the theory of martingales. Particular gratitude goes to H. Jarchow (Zürich) for various helpful remarks.
For many years, our research on this subject was supported by the Deutsche Forschungsgemeinschaft, contracts Ko 962/3–1 and Pi 322/1–1.
Finally, we thank CAMBRIDGE UNIVERSITY PRESS for their excellent collaboration in publishing this book. Jena, October 1997 ALBRECHT PIETSCH JÖRG WENZEL