The objective of the proposal is to investigate the important processes of biofilm detachment As a specific case, within the human body biofilms detach from the surfaces of host tissues and indwelling devices to spread infection. More generally, biofilms grow on a range of environmental and industrial surfaces. Some harbor pathogens from contaminated food, water, or aerosols: detachment causes the transfer of pathogens within the environment and into contact with people. The investigation will cover how to assess and measure the propensity for detachment and reattachment. The products of this research are vital to the general area of risk assessment and disease control. The proposal involves an international collaboration between two leaders of biofilm research (Dr. J. William Costerton at Montana State University and Dr. Hilary Lappin-Scott at University of Exeter, U.K.) Both are international experts in biofilm research. To give examples, they were the organizers of the ASM Special Topics conference on Biofilms (Snowbird, Utah, 1996), and have jointly edited a textbook on the subject. In addition to having active individual research interests, Drs. Costerton and Lappin-Scott have a successful long- term partnership that has produced many significant studies. This relationship has led to the development of a unique and complementary research strength.