Four years ago The Blue Light Syndrome was published as the Proceed ings of the 1 st International Conference on the Effect of Blue Light in Plants and Microorganisms. Subsequently the interest in this fascinating and growing field of re search has further increased, as is reflected by numerous publications. Blue light effects cover such a wide spectrum of organisms, responses and methods that communication among scientists with backgrounds in biology, biochemistry, and biophysics is particularly necessary. These facts not only justified, but demanded calling the "Blue Light Family" together again. In spite of many fmancial problems, the second confer ence attracted 113 active members from 19 countries. The 2nd International Conference on The Effect of Blue Light in Plants and Microorganisms was held in July 1984, like the first at the University of Marburg. The organizer could again rely on the help of the International Advisory Committee (W. Briggs, Stanford; M. Furuya, Tokyo; J. Gressel, Rehovot; S. Miyachi, Tokyo; W. Rau, Miinchen; J. Schiff, Waltham; P .-S. Song, Lubbock). The very generous financial as sistance from the DFG and the support of the Philipps-Universitat Mar burg and its Sonderforschungsbereich "Zellenergetik and Zelldifferen zierung" were the prerequisites to organizing the conference. The present book consists of 56 original papers. The partitioning into eight chapters is always a problem. The grouping of different aspects of the papers into these chapters has not always been obvious, so that one or the other contribution could possibly fit in another chapter.

The goals of the science of photobiology can be divided into four categories: to develop (I) ways to optimize the beneficial effects of light on man and his environment, (2) methods to protect organisms, including man, from the detrimental effects of light, (3) photochemical tools for use in studies of life processes, and (4) photochemical therapies in medicine. To achieve these goals will require the knowledgeable collaboration of biologists, chemists, engineers, mathematicians, physicians, and physicists; because photobiology is a truly multidisciplinary science. While a multidis ciplinary science is more intellectually demanding, it also has a greater potential for unexpected breakthroughs that can occur when data from several areas of science are integrated into new concepts for theoretical or practical use. Photochemical and Photobiological Reviews continues to provide in depth coverage of the many specialty areas of photobiology. It is hoped that these reviews will provide an important service to the younger scientists in the field and to senior scientists in related fields, because they provide a ready access to the recent literature in the field, and more importantly, they frequently offer a critical evaluation of the direction that the field is taking, or suggest a redirection when appropriate. Since it is important that this review series remain responsive to the needs of photochemists and photobiologists, the Editor would value com ments and suggestions from its readers.

The Congressional Record is the official record of the proceedings and debates of the United States Congress. It is published daily when Congress is in session. The Congressional Record began publication in 1873. Debates for sessions prior to 1873 are recorded in The Debates and Proceedings in the Congress of the United States (1789-1824), the Register of Debates in Congress (1824-1837), and the Congressional Globe (1833-1873)

It is not always the case that the subject of a scientific book and its relevance to everyday li fe are so timely. Photobiology and its si ster subject Radiobiology are now a must for understanding the environment we live in and the impact light, ultraviolet light, and radiation have on all aspects of our life. Photobiology is a true interdisciplinary field. Photobiology research plays a direct role in diverse fields, and a glance at the topics of the symposia covered in this book by over 100 articles shows the breadth and depth of knowledge acquired in fundamental research and its impact on the major issues and applied problems the world is facing. Half a century of photobiology research brought about an understanding of the importance of light to life, both as a necessary source of energy and growth as weIl as its possible dangers. Research in photochemistry and photobiology led to the discoveries of ceIlular repair mechanisms of UV induced damages to DNA and this led to understanding of the effects of hazardous environmental chemieals and mutagenecity , and to the development of genetic engineering. This topic was given due emphasis in several symposia and chapters in this book.