In February, 1974, an 'International Workshop on Membrane Transport in Plants' was held at the Nuclear Research Centre, JLiI ich, West Germany. More than two hundred and fifty people, from fourteen countries, took part in this highly successful meeting. A somewhat similar meeting took place in Liverpool, England, two years ago and it became clear there that progress in the field of membrane transport in plants was now so marked that a second, and wider, meeting in Germany was more than fully justified. The members of our pro gramme committee (U. Zimmermann, Chairman, JLilich (FRG); J. Dainty, Toronto (Canada); F. FLihr, JLilich (FRG); N. Higinbotham, Pullman, Wa. (USA); A. B. Hope, Adelaide (Australia); A. Lev, Leningrad (USSR); U. LLittge, Darmstadt (FRG); HW. NLirnberg, JLilich (FRG); E. A. C. MacRobb-ie, Cambridge (UK); H. Stieve, JLilich (FRG); M. Thellier, Rouen (France); K. Wagener, JLilich (FRG)) decided on a broad spectrum of topics including thermodynamics of transport processes, water relations, primary reactions of photosynthesis, as well as the more conventional aspects of membrane transport. They were thus, for instance, particularly concerned to bring advanced thermodynamical concepts to the attention of biologists and to show physical chemists what the more complex biological systems were like. We have taken considerable editorial liberty with the manuscripts submitted for this book, for we were very conscious of the necessity to make all papers understandable by as wide a circle of readers as possible."