The fateful days of the great stock market crash entered modem history almost 50 years ago to this day. The cyclic turning point of the U. S. economy oc curred, however, around June 1929, and economic activity receded substantial ly over the subsequent months. The onset of an economic downswing thus became clearly visible before the famous crash. But the October event stays in the public's mind as the symbol of the Great Depression. For nearly four years, until the spring of 1933, the U. S. economy plunged into a deep reces sion. Activity declined, prices fell, and there emerged a massive unemploy ment problem. The economy ultimately overcame this shock in 1933. Prices rose rapidly in spite of substantial margins of unusual resources. Activity ex panded, but occasionally at a somewhat hesitant rate. The expansion, however, was interrupted by another recession of major proportions during 1937-38. The tragic sequence of events shaped public consciousness and influenced new approaches and views in economic policymaking. The activist approach to "stabilization policy" and a wide range of regulatory policies were essentially justified in terms of this experience. These policies were crucially influenced by our understanding and interpretation of the Great Depression. The view of a radically unstable economic process perennially on the edge of serious collapse gained wide popularity and became a central element of the Keynesian tradi- 2 INTRODUCTION tion. It encouraged, with supplementary interpretations, an interventionist and expanding role of the government in our economic affairs."

The productive work of widely distributed academic research has contributed substantially, over the postwar period, to important advances in our understanding. It has also offered a clearer recognition of many unresolved problems. Never theless, the progress achieved over the last decades, ex hibited by the systematic application of "theory" to actual issues and observable problems, could not overcome a per vasive sense of dissatisfaction. Some academic endeavors pursued within a traditional range of economic analysis have appeared increasingly remote from broad social issues, motivating the social and intellectual unrest experienced in recent years. Conditioned by the traditional use of economic analysis, many have naturally concluded that the "most relevant" social issues agitating our times are beyond the reach of economics. Purist advocates of a traditional view thus condemn any extension of economic analysis to social issues as an escape into "ideology." Others argue the need for an "interdisciplinary approach" involving sociology, social psychology, or anthropology as necessary strands in a useful understanding of social, institutional, and human problems of contemporary societies. We note here, in par ticular, the subtle attraction inherent in Marxian thought. It appears to offer a unified approach, with a coherent inter pretation, to all matters and aspects of human society, in cluding even nature."

Klaus-Peter Schwarz, lAG President The University of Calgary The Scientific Assembly of the International Association of Geodesy (lAG) was held from September 3 to 9, 1997 in Rio de Janeiro, Brazil, in conjunction with the 18th Brazilean Congress of Carthography. This was the first time that one ofthe major lAG meetings took place in Brazil. It provided an opportunity to showcase the progress of geodetic work in South America through campaigns such as SIRGAS. It also provided an opportunity for a large group of international experts to present the state of the art in ge- odesy and geodynamis and to interact with their hosts on possibilities of future coopera- tion. For the lAG, it continued a trend, started in Beijing four years ago, to hold major geodetic meetings outside of Europe and North America. The International Geoid School which was held in Sao Paulo following this meeting showed another facet of this grow- ing internationalization ofIAG activities and services. The scientific program of the meeting consisted of three symposia and two special ses- sions, namely Symposium 1 : Advances in Positioning and Reference Frames Symposium 2: Gravity and Geoid Symposium 3: Geodynamics Special Session 1: lAG Services Special Session 2: Geodesy in Antartica. Papers presented at the first symposium are published in volume 1 of these proceedings, while papers of symposia 2 and 3 as well as special session 2 are contained in volume 2. Papers presented at special session 1 will be published separately.

Klaus-Peter Schwarz, lAG President The University of Calgary The Scientific Assembly of the International Association of Geodesy (lAG) was held from September 3 to 9, 1997 in Rio de Janeiro, Brazil, in conjunction with the 18th Brazilean Congress of Carthography. This was the first time that one ofthe major lAG meetings took place in Brazil. It provided an opportunity to showcase the progress of geodetic work in South America through campaigns such as SIRGAS. It also provided an opportunity for a large group of international experts to present the state of the art in ge- odesy and geodynamis and to interact with their hosts on possibilities of future coopera- tion. For the lAG, it continued a trend, started in Beijing four years ago, to hold major geodetic meetings outside of Europe and North America. The International Geoid School which was held in Sao Paulo following this meeting showed another facet of this grow- ing internationalization ofIAG activities and services. The scientific program of the meeting consisted of three symposia and two special ses- sions, namely Symposium 1 : Advances in Positioning and Reference Frames Symposium 2: Gravity and Geoid Symposium 3: Geodynamics Special Session 1: lAG Services Special Session 2: Geodesy in Antartica. Papers presented at the first symposium are published in volume 1 of these proceedings, while papers of symposia 2 and 3 as well as special session 2 are contained in volume 2. Papers presented at special session 1 will be published separately.

This selection of papers emphasizes the advances in the field and covers a wide range of topics in geophysics, geodynamics, and oceanography to which modern geodesy is contributing.

This study offers a systematic analysis of basic questions relating to equitable income taxation. Of course, a definite solution, resting on scientific arguments, cannot be expected for this important field of government activity. However, what is possible, is an exhaustive dis cussion of various aspects of equitable income taxation, thus preparing the ground for reasonable political decisions. I hope that the present book will contribute to this continuing discus sion, presenting results from modern social-choice theory and optimum taxation theory in order to gain further insights into the problem of income taxation. On a fundamental level, social-choice theory is applied in order to in vestigate the normative foundation of different tax rules. Arrow's im possibility theorem forms the starting point of the analysis; as was shown by recent contributions to social-choice theory, this impossibi lity result can be overcome if various degrees of interpersonal utility comparisons are admitted. Using this approach, one can work out the general norms of equity behind familiar tax rules. As a special point, the traditional principle of equal proportional sacrifice will be given a social-choice theoretic foundation in this book. The second level on which tax rules can be discussed, concerns their respective consequences in concrete taxation models. TWo such models are specified in this study, the first one takes gross income of the taxpayers as given, it is contrasted with the second, more complex mod el, where the individual labour-leisure decision is taken into account.

It is a very special honour for me to be able to present this handbook of medical oncology, which under diverse headings and origins covers such a vast spectrum of experience. I be lieve the reader will be struck in particular by the impressive volume of information available, especially with regard to childhood tumours, which represent, today, an immense "lab oratory of hope". It is in this very field that we oncologists have been able to obtain the most consoling results in recent years. I feel sure that all those who read these chapters will find that their oncological competence is enriched and also in a certain sense that their wish to contribute to progress in can cer research and treatment has been renewed. In conclusion, my most heartfelt congratulations go to the authors for the excellent job they have done, as well as my ad miration for having been able to concentrate so much pre cious and innovative information into so little space. Umberto Veronesi Preface Since 1976, the VICC has been holding chemotherapy courses in all parts of the world, excluding North America and Australia. The Manual of Cancer Chemotherapy, origi nally devised as a didactic tool to be used by course partici pants, expanded itself in the successive editions to a compre hensive, although schematic, textbook of medical oncology.