This work examines the issue of accelerated soil erosion, which has become an increasingly serious concern in the twentieth century. Aspects considered include on-site impact of erosion; application of soil science to problems of non-agricultural uses of soil, such as mineland restoration, urban uses and disposal of urban wastes; soil contamination and pollution by industrial activities; and athletic and recreational uses of soil. Soil Quality and Soil Erosion will be a useful text for soil scientists, agronomists, foresters, and environmental scientists as we enter the next century.

This work examines the issue of accelerated soil erosion, which has become an increasingly serious concern in the twentieth century. Aspects considered include on-site impact of erosion; application of soil science to problems of non-agricultural uses of soil, such as mineland restoration, urban uses and disposal of urban wastes; soil contamination and pollution by industrial activities; and athletic and recreational uses of soil. Soil Quality and Soil Erosion will be a useful text for soil scientists, agronomists, foresters, and environmental scientists as we enter the next century.

Of all the food produced in the world one third is lost to insect pests, weeds and diseases, and the total world population is estimated as growing from 4000 million in 1975 to about 6000 million by the year 2000. To satisfy these needs, the world's farmers must meet the extra requirement every year. The easiest way in which farmers can increase the amount of food they produce is to prevent the loss due to pests. The biological control measures which were once thought to be the safest methods of pest control have, as we now know, not proved successful on a commercial scale. In such a dismal situation the only solution is to use pesticides to save the losses from pests and to increase the crop yield. Apart from agriculture, pesticides have also contributed much to human com fort by controlling the vectors of typhoid, malaria, sleeping sickness, filariasis, dengue hemorrhage fever, plague etc. On the other hand, the indiscriminate use of insecticides and their harmful effects on nontarget organisms has attracted much attention from people in all walks of life, for example, scientists, administrators, the press and the public. The harmful effects of insecticides on higher organisms such as birds, fish and mammals are easy to observe and have received much attention. However, the interactions of insecticides with microorganisms such as bacteria, fungi, algae and protozoa have gone unnoticed until recently."

The world needs for food and fiber continue to increase. Population growth in the developing countries peaked at 2. 4% a year in 1965 and has fallen to about 2. 1%. However, in many developing countries almost half the people are under 15 years of age, poised to enter their productive and reproductive years. The challenges to produce enough food for this growing population will remain great Even more challenging is growing the food in the areas of greatest need. Presently the world has great surpluses of food and fiber in some areas while there are devastating deficiencies in other areas. Economic conditions and the lack of suitable infrastructure for distribution all too often limit the alleviation of hunger even when there are adequate supplies, sometimes even within the country itself. World hunger can be solved in the long run only by increasing crop production in the areas where the population is growing most rapidly. This will require increased efforts of both the developed and developing countries. Much of the technology that is so successful for crop production in the developed countries cannot be utilized directly in the developing countries. Many of the principles, however, can and must be adapted to the conditions, both physical and economic, of the developing countries.

The purpose of Advances in Soil Science is to provide a forum for leading scientists to analyze and summarize the available scientific information on a subject, assessing its importance and identifying additional research needs. A wide array of subjects has been addressed by authors from many countries in the initial ten volumes of the series. The quick acceptance of the series by both authors and readers has been very gratifying and confirms our perception that a need did exist for a medium to fill the gap between the scientific journals and the comprehensive reference books. This volume is the first of the series devoted entirely to a single topic soil degradation. Future volumes will include both single-topic volumes as well as volumes containing reviews of different topics of soil science, as in the case of the first ten volumes. There are increasing concern and attention about managing natural re sources, particularly soil and water. Soil degradation is clearly one of the most pressing problems facing mankind. Although the spotlight regarding soil degradation in recent years has focused on Africa, concern about the degradation of soil and water resources is worldwide. The widespread con cern about global environmental change is also being linked to severe problems of soil degradation. Therefore, we are indeed pleased that the first volume of the series devoted to a single topic addresses such an impor tant issue. The current volume is also the first of the series involving a guest editor."

Soil degradation is clearly one of the most pressing problems facing man kind. A continuation of soil degradation will eventually lead to a loss in crop productivity even though fertilizers and other inputs often result in increased yields in the short term. Soil degradation also leads to environ mental pollution. A decrease in soil quality invariably leads to a decrease in water quality, and often in air quality. While there is a clear consensus that soil degradation is a major problem, the literature on this subject leaves numerous baffling questions. If statis tics on land degradation are correct, there is a definite cause for concern, and present a mammoth challenge for agricultural scientists. There are those that say the scientific community has over dramatized this issue, and created a credibility problem. Consequently; Volume 11 of Advances in Soil Science was organized by Dr. Rattan Lal who is recognized as a lead ing authority on the subject. The objective of Volume 11 was to assess the types and processes of soil degradation and establish some of the major cause-effect relationships. Volume II documented the seriousness of soil degradation in many parts of the world. Therefore, it seemed immediately important to devote a volume to the principles and technologies for restor ing degraded soils to a productive status. While the land resources are limited, world population is rapidly increasing, particularly in developing countries. Dr."

The study of soils has taken on increased importance because a rapidly expanding population is placing demands on the soil never before experi enced. This has led to an increase in land degradation. Land degradation is one of the most severe problems facing mankind. Volume 11 of Advances in Soil Science was devoted entirely to this critical area of soil science. The editors of that volume, R. Lal and B.A. Stewart, defined soil degradation as the decline in soil quality caused by its misuse by humans. They further stated that soil degradation is a major concern for at least two reasons. First, it undermines the productive capacity of an ecosystem. Second, it affects global climate through alterations in water and energy balances and disruptions in cycles of carbon, nitrogen, sulfur, and other elements. Through its impact on agricultural productivity and environment, soil deg radation leads to political and social instability, enhanced rate of deforesta tion, intensive use of marginal and fragile lands, accelerated runoff and soil erosion, pollution of natural waters, and emission of greenhouse gases into the atmosphere. In fact, soil degradation affects the very fabric of mankind."

As the semiconductor industry attempts to increase the number of functions that will fit into the smallest space on a chip, it becomes increasingly important for new technologies to keep apace with these demands. Photomask technology is one of the key areas to achieving this goal. Although brief overviews of photomask technology exist in the literature, the Handbook of Photomask Manufacturing Technology is the first in-depth, comprehensive treatment of existing and emerging photomask technologies available. The Handbook of Photomask Manufacturing Technology features contributions from 40 internationally prominent authors from industry, academia, government, national labs, and consortia. These authors discuss conventional masks and their supporting technologies, as well as next-generation, non-optical technologies such as extreme ultraviolet, electron projection, ion projection, and x-ray lithography. The book begins with an overview of the history of photomask development. It then demonstrates the steps involved in designing, producing, testing, inspecting, and repairing photomasks, following the sequences observed in actual production. The text also includes sections on materials used as well as modeling and simulation. Continued refinements in the photomask-making process have ushered in the sub-wavelength era in nanolithography. This invaluable handbook synthesizes these refinements and provides the tools and possibilities necessary to reach the next generation of microfabrication technologies.