The suggestion for a symposium on microbial ecology was first put forward by Professor J.A.R. Miles in 1972. After gaining support from the New Zealand Microbiological Society and the Royal Society of New Zealand. a national committee with international represen­ tatives and a local committee were formed. Sponsorship was obtained from UNEP, UNESCO, ICRO and IOMS. IUBS and ICOME and the culmina­ tion was the First International Microbial Ecology Symposium in 1977 attended by over 400 scientists from 30 countries. Certain facets of microbial ecology have been studied for over a century, but the recognition of microbial ecology as a discipline has come relatively recently. The National Committee decided that all aspects of microbial ecology should be discussed at the Sym­ posium. The local organising committee, therefore. invited papers on the ecology of microorganisms and viruses associated with plants and animals, as well as microorganisms associated with soil and water and with general environmental problems. Of the 240 papers presented. only a selection is published here. It is hoped that they will be of interest particularly to those who could not attend. The vol ume stands as a tribute to the fore­ sight of John Miles in instigating the symposium and who retires this year from the Microbiology Department of the University of Otago where he has had a distinguished career. May his interest in microbial ecology long continue.