The photosynthetic bacteria are amongst the most versatile of photosynthetic organisms, in terms of the habitats in which they thrive, the diversity of their physiological processes and in aspects of their biochemistry. The VIIth International Symposium on Photosynthetic Prokaryotes (the first such to be held in the USA) will bring together scholars from around the globe to assess recent progress in understanding the bioconversion of radiant energy (light) into that of the chemical bond energy found in the biomass of these organisms. Partial financial support of the VIIth International Symposium on Photosynthetic Prokaryotes will make it possible for young US scientists to take part in this conference. Recent progress in the events involved in harvesting the energy of light by converting it into more biologically useful forms, in the form of cellular compounds, will be the focus of the symposium.