Dr Ian Pepper is an environmental microbiologist specializing in the molecular ecology of the environment. He is is director of both the Environmental Research Laboratory and the National Science Foundation Water Quality Center, both at the University of Arizona.  He is also a professor and research scientist with the Department of Soil, Water, and Environmental Science, and the Department of Microbiology and Immunology at the University of Arizona. He holds a B.Sc. from the University of Birmingham, Great Britain, and an M.S. in Soil Biochemistry and Ph.D. in Soil Microbiology from Ohio State University. Dr. Pepper has published extensively on such subjects as plant and soil microbes, microorganisms and metal pollutants, and enteroviruses in marine waters. He recently served on the U.S. National Research Council's Committee on Research Priorities for Earth Science and Public Health. Soil impacts human health by being a vehicle for safe, nutritious food production and a source of natural products. In addition, soils are a source of indigenous human pathogens and a sink for introduced human pathogens. Soils are also the living biofilter that protects surface and ground waters from emerging contaminants. For food production, the biggest challenges will be to maintain the available acreage of agricultural land worldwide, and to also maintain its productivity. Sustainability is currently the term in vogue, and at the heart of soil sustainability is the requirement of maintaining soil organic matter levels. One approach to maintaining these levels is to utilize a vast world wide resource that is currently under-utilized, namely organic wastes of animal and human origin. Land application of animal manures and human biosolids would provide trillions of pounds of organic material annually to carbon-starved soils, particularly in arid and semi-arid lands. To utilize these wastes safely, worldwide guidelines for land application should be developed and coordinated with agencies such as the World Health Organization and the UN Food and Agriculture Organization. Additional opportunities to enhance food production include the use of new microbial fertilizers and pesticides, which promote uptake of pre-existing soil nutrients and reduce inputs of anthropogenic compounds. A family living on a quarter acre of land is surrounded by approximately a million million million soil bacteria. This vast diverse population offers a treasure chest of opportunities to provide new antibiotics and cancer fighting agents. Strategies for obtaining natural products are now emerging that utilize new cloning techniques applied to non-culturable bacteria obtained through community DNA extracted from soils.