"Are the Great Lakes getting better or worse?" - this is the question that the public, scientists and managers are asking the International Joint Commission after a quarter-century of co-operative action by the United States and Canadian governments to clean up the Great Lakes. This volume contains papers from the workshop on Environmental Results, hosted in Windsor, Ontario, by the Great Lakes Science Advisory Board of the International Joint Commission, on September 12 and 13, 1996. The Great Lakes have been through almost a century of severe pollution from the manufacture, use and disposal of chemicals. In the 1960s wildlife biologists started to investigate the outbreaks of reproductive failure in fish-eating birds and ranch mink and to link these to exposure to organochlorine compounds. Human health researchers in the 1980s and 1990s linked growth retardation, behavioural anomalies and deficits in cognitive development with maternal consumption of Great Lakes fish prior to pregnancy. The Great Lakes became the laboratory where the theory of endocrine disruptors was first formulated.