The First International Congress on DNA Damage and Repair was held in Rome, Italy, July 12-17, 1987. It was organized by the Italian Com mission for Nuclear Alternative Energy Sources. The subject of DNA damage and repair involves almost all the fields ofbidogical sciences. Some of the more prominent ones include carcino genesis, photobiology, radiation biology, aging, enzymology, genetics, and molecular biology. These individual fields have their own interna tional meetings and although the meetings often have sessions devoted to DNA repair, they do not bring together a wide diversity of international workers in the field to exchange ideas. The purpose of the Congress was to facilitate such an exchange among scientists representing many fields of endeavor and many countries. The 37 manuscripts in this volume, presented by the invited spea kers during the four and half days of the Congress, encompass the field of DNA damage and repair. They cover biological systems ranging from mo lecules to humans and deal with damages and repair after treatment of cells with various types of radiations, chemicals, and exogenous and en dogenous oxidative damages. The Congress and its Proceedings are dedicated to two international leaders in the field of DNA damage and repair, Alexander Hollaender of the United States and Adriano Buzzati Traverso of Italy. Hollaender, who died in December 1986, was one of the first investigators to recognize the damage to DNA was important in cell killing and mutagenesis. His early work indicated that cells could recover from radiation injury."

The study of the interaction between light and matter has played a fundamental role in the development of natural sciences. Synchrotron radiation has characteristics of intensity, width and continuity of \Jave length range, time structure, tunability and polarization which are far superior to those of most other sources. It is possible with synchrotron radiation to perform experiments ~Jhich could previously be only thought about and to routinely carry out measureEents ~Jhich were once made only with great dif- ficulties. The study of the enormously complicated but imF-ensely interesting biological structures seems to be particularly suited to this new approach. The above considerations lead us to consider the opportunity of critically discussing the achievements and perspectives of the use of synchrotron radiation in biology and presenting them to a selected audience within the framework of an advanced school. From the very beginning we were encouraged in our initiative by many discussions with colleagues in the Rome area, who were later to become r.:.embers of the Scientific Committee of this Course. \oie were fully aware that ~y of the results obtained so far were of a pre- liminary nature; we feIt, however, that they were sufficiently promising to justify this venture, which seemed particularly im- portant in consideration of the increasing nur.:.ber of centers, where synchrotron radiation is becoming available.

Every four years the photobio1ogists of the world get together in an International Congress. They discuss and learn not only re search details and findings in their own, often narrow, fields but educate one another broadly in the many biological systems that interact with light. It is this latter purpose that is exemplified by these proceedings - the Symposium papers and Workshop summaries of the VIIth International Congress on Photobiology held in Rome, August 29 - September 3, 1976. Photobiology is one of the few true interdisciplinary fields. It has an air of excitement about it. A glance at the table of contents indicates clearly that photobiology and its practitioners (individuals whose primary interests are in medicine, plant sci ences, animal sciences, molecular properties, and energy conversion) interact with the entire and diverse world of living creatures. We supply not only the basic research background to help evaluate many present-day environmental problems but are also evaluating and pointing the way toward solutions to a number of these problems."

The identification and quantitation of environmental risk in humans is one of the main problems to be solved in order to improve the protection of individuals and of human populations against phys ical and chemical pollutants. Epidemiology plays a central role in the evaluation of health risk directly in human populations. In this volume are collected 33 lectures presented at the AS course on "Epidemiology and quanti tat ion of environmental risk in humans from radiation and other agents: potential and limitations," sponsored by NATO and Italian Association of Radiobiology and or ganized by ENEA. The course has been devoted to a number of aspects of environ mental risk analysis and evaluation based on epidemiological in vestigation. Basic epidemiological concepts and methods have been reviewed. Fundamentals of dosimetry and microdosimetry were presented in re lation to the contribution of epidemiology in defining the dose effect relationships for radiation carcinogenesis and its relation with age, sex and ethnicity. The mechanisms of carcinogenesis as a multi-stage process were illustrated. One of the main topics was 'cancer epidemiology' and its cor relation with: - occupational and non-occupational exposure to ra diation - diagnostic and therapeutic irradiation - cancer proneness - hereditary and familiar diseases - abnormal response to carcino gens - environmental pollution in air and water - exposure to radon in mines and in building material - atomic bomb explosion - chemo therapy - dioxin and related compounds."