Biological fixation of nitrogen by organisms and associations other than those concerned in the legume-Rhizobium symbiosis has attracted increasing attention since the firstintemationalworkshop on the theme at Piracicaba, Brasil, in 1979. Approximately 150 scientists gathered on September 2-8, 1984, at the Hanasaari Cultural Centre near Helsinki, Finland, for the third international meeting on nitrogen fixation with non-legumes. Forty-two papers and 39 posters were presented; 32 of the papers have been broughttogetherin this publication. The Symposium was generously sponsored by the...