At a meeting of the Federation of European Societies of Plant Physiology in 1984 in Strasbourg the idea of having a special meeting on inorganic nitrogen metabolism on a more or less European level was born. Originally it was planned to limit its content to the inorganic nitrogen metabolism of eukary­ otic algae and cyanobacteria, but later the Organizing Committee decided to widen the scope of the meeting. Thus, what resulted was a Symposium, or rather an Advanced Course, on Inorganic Nitrogen Metabolism, including, in addition to algal biochemistry and physiology, some coverage of nitrogen­ fIxing bacteria, a large area that could only be touched on during the course and in which newer ideas from molecular biology are much involved, and, to some extent, of the biochemistry and physiology of fungi and higher plants. Not all of the speakers originally invited could come and contribute, but the Table of Contents shows that the meeting was able to survey reasonably adequately, the present state of research on nitrogen assimilation by plants. The speakers were asked to present recent results from their laboratories in the context of a survey of background knowledge, thus the articles in this volume sometimes partially overlap, but never so much that there is not an interesting and complementary approach to the same problem from several sides. Therefore, the editors decided not to interfere with the texts of the authors and to risk some repetition; e. g.