The Second International Congress on Photosynthesis Research took place in Stresa, Italy during June 24-29, 1971; two centuries after the discovery of Photosynthesis by Joseph Priestley in 1771. This important anniversary was celebrated at the Congress by a learned account of Priestley's life and fundamental discoveries given by Professor Robin HILL, F. R. S. Professor HILL's lecture opens the first of the three volumes which contains the contributions presented at the Congress. The manuscripts have been distributed into three volumes. Volume I con tains contributions in the areas of primary reactions and electron transport; Volume II ion transport and photophosphorylation, and Volume III carbon assimilation, regulatory phenomena, developmental aspects, and from the two special sessions of the Congress devoted to evolution and photorespiration. It is realized that this division is necessarily somewhat arbitrary since many contributions relate to more than one of the above mentioned titles. However, the large number of contributions (over 3000 typed pages) made it impossible to publish the proceedings in less than three volumes. The printing of these volumes and the organization of the Congress were made possible by a contribution from the Consigio Nazionale delle Ricerche of Italy. The generous support of the Istituto Lombardo Acca demia di Scienze e Lettere to the publication of these proceedings is gratefully acknowledged. The editors wish to express their appreciation to all the scientists who contributed the results of the investigations, for their coopera tion; and to Drs."

As editor of the two-part Volume V on photosynthesis in RUHLAND'S Encyclopedia, the forerunner of this series published in 1960, I have been approached by the editors of the present volume to provide a short preface. The justification for following this suggestion lies in the great changes which have been taking place in biology in the two decades between these publications, changes which are reflected in the new editorial plan. Twenty years ago it appeared convenient and formally easy to consider photo synthesis as a clearly separated field of research, which could be dealt with under two major headings: one presenting primarily photochemical and biochemical prin ciples, the other physiological and environmental studies. Such a partition, however, as far as aims and opinions of the authors were concerned, resulted in a rather heterogeneous volume. Today, the tendency in experimental biology is towards a merger of previously distinct disciplines. Biochemists and biophysicists have developed their methods to such an extent that, over and above the analysis of individual reaction sequences, work on the manifold interrelationships among cellular activities has become in creasingly possible. Joining them in growing numbers are the physiologists and ecologists with their wealth of information on activity changes in vivo and on the variability and efficiency of the organisms concerned. Furthermore, biochemists, biophysicists and physiologists also now share a lively interest in ultrastructure research, the results and implications of which, through continually improving methodology, have generated important stimuli for the work in the field of cell function."

The Second International Congress on Photosynthesis Research took place in Stresa, Italy during June 24-29, 1971; two centuries after the discovery of Photosynthesis by Joseph Priestley in 1971. This important anniversary was celebrated at the Congress by a learned account of Priestley's life and fundamental discoveries given by Professor Robin HILL, F. R. S. Professor HILL's lecture opens the first of the three volumes which contains the contributions presented at the Congress. The manuscripts have been distributed into three volumes. Volume I con tains contributions in the areas of primary reactions and electron transport; Volume II ion transport and photophosphorylation, and Volume III carbon assimilation, regulatory phenomena, developmental aspects, and from the two special sessions of the Congress devoted to evolution and photorespiration. It is realized that this division is necessarily somewhat arbitrary since many contributions relate to more than one of the above mentioned titles. However, the large number of contributions (over 3000 typed pages) made it impossible to publish the proceedings in less than three volumes. The printing of these volumes and the organization of the Congress were made possible by a contribution from the Consigio Nazionale delle Ricerche of Italy. The generous support of the Istituto Lombardo Acca demia di Scienze e Lettere to the publication of these proceedings is gratefully acknowledged. The editors wish to express their appreciation to all the scientists who contributed the results of the investigations, for their coopera tion; and to Drs."

Proceedings of the IInd International Congress on Photosynthesis Research, Stresa, Italy, June 24-29, 1971