Journalists, always very direct and in search of sensation, essentially asked me two questions on the occasion of this workshop: What were the goals of the meeting? With the improvement of diagnosis through the development of image techniques, didn't the contrast media already have their future behind them? Many answers were provided during the course of the workshop, and in order to best answer the journalists I proposed the following synopsis. 1. Since the 1979 Colorado Springs workshop organized by E. Lasser, progress has been so rapid and the newly available works so numerous that another meeting on an international level for the purpose of pre­ senting and discussing these advances appeared indispensable. Why not then in Europe and why not in Lyon? To expand on this progress, by 1981 the new contrast media with less-hyperosmolar molecules, still in the trial stage in 1979, were almost all available commercially for angiography, albeit at prohibitive prices. The advantages of these various media are becoming better known; moreover, in the wake of Lasser's work, our understanding of the pathophysiology of their noxious effects is also advancing rapidly owing to the use of models (for the target organs: heart, vessel wall, nervous system, kidney; and for the more general reactions: blood cells, coagulation, complement system, circulating enzymatic systems). In addition, further new molecules are currently being studied in research laboratories. 2.