Every four years the photobio1ogists of the world get together in an International Congress. They discuss and learn not only research details and findings in their own, often narrow, fields but educate one another broadly in the many biological systems that interact with light. It is this latter purpose that is exemplified by these proceedings - the Symposium papers and Workshop summaries of the VIIth International Congress on Photobiology held in Rome, August 29 - September 3, 1976. Photobiology is one of the few true interdisciplinary fields. It has an air of excitement about it. A glance at the table of contents indicates clearly that photobiology and its practitioners (individuals whose primary interests are in medicine, plant sci­ ences, animal sciences, molecular properties, and energy conversion) interact with the entire and diverse world of living creatures. We supply not only the basic research background to help evaluate many present-day environmental problems but are also evaluating and pointing the way toward solutions to a number of these problems.