Professor Joseph Connell has been a major international figure in ecology for the past five decades. His PhD research began the field of experimental marine ecology and has stimulated hundreds of experimental studies that have explored the physical and biological determinants of the distribution and abundance of species. More recently, Connell has focussed on the important question of the determinants of biodiversity, particularly in Australian coral reefs and rainforests. He has made an enormous contribution to Australian science and to the research groups and many Australian researchers with whom he has interacted. Connell has also made major contributions to theoretical aspects of ecology, and to important practical applications of ecological theory. In 1985, he was awarded the prestigious Eminent Ecologists award of the Ecological Society of America. Five of Connell's publications, have been designated by Current Contents as "Citation Classics", reflecting his profound influence on the field of ecology.