The 9th International Conference on Plant Growth Substances was held at the University of Lausanne, August 30-September 4, 1976. This meet ing was sponsored by the National Swiss Foundation for Scientific Re search (FNRS), the Fonds Herbette of the Faculty of Sciences of Lau sanne, by several other official sources, and by a few Swiss indus tries. The conference was attended by over 420 scientists, represent ing 42 countries, with a total of 550 participants. Our 9th conference was rather different from the previous ones. The usual short submitted papers followed by a too brief discussion were replaced by three kinds of scientific communications. First in the reports, authors gave a critical analysis of a selection of broad to pics, directing their comments to new perspectives of research and me thodology. Second, the paper demonstrations, presented by over 200 scientists, induced large and fruitful discussions and ensured that personal contacts were made. Finally, during four workshops, several interesting points - introduced in the reports and paper demonstra tions - were developed and discussed.