In May 1977, René Dubos composed a letter to the University of Georgia biologist Eugene Odum. Then aged 76, Dubos was at the height of his fame as a popular medical and scientific thinker. In a 50-year-career that had taken in a PhD in soil microbiology at Rutgers University, the isolation of the first antibacterial agents in Oswald Avery's laboratory at the Rockefeller Institute for Medical Research in New York, and pioneering studies of turberculosis and the role of intestinal microflora in the regulation of health and disease, the French-born medical researcher had increasingly decried short-term technological fixes that he feared might upset the delicate balance between humans and microbes. In this way, Dubos had come to be regarded as an apostle for the burgeoning environmental movement and a defender of the view of the earth as a delicate ecosystem. It was a view that he shared with Odum, not least because it was Odum who had brought the ecosystems concept to wider popular audiences through his 1953 book Fundamentals of Ecology, and who had helped establish ecology as a scientific discipline in American universities. In theory then, the researchers had much in common. However in 1977 when Dubos discovered that Odum was to be presented with the Tyler Award for thinkers who had made a significant contribution to ecology and environmental science -- the same award that Dubos had been presented with the previous year -- the Frenchman blanched. "You are for me Mr Ecology," he informed Odum. "Although I know I am not an ecologist, I have repeatedly been involved in scientific problems which have ecological components. This is happening once more in an enterprise that will certainly be my last professional activity."