International Symposia sponsored by ClBA Basle have been held once a year since 1959 in various European countries. In con­ trast to the many scientific meetings organised by the ClBA FOUN­ DATION either at its headquarters in London or occasionally abroad, the subjects dealt with at these International Symposia have concerned problems more directly related to ClBA'S own research work in the pharmaceutical field. The various topics covered up to the present reflect the far-reaching interests and the wide­ spread activities that a pharmaceutical enterprise develops in quite diverse fields of chemical, biological, and medical research, and to which the ba.sic approach is an increasingly important prerequisite for the development of a new and useful therapeutic agent. Iron metabolism came into the sphere of interest in connection with CIBA'S research on antibiotics and related natural products containing iron, substances which act in their metal-free form as strong and specific chelating agents. Of course, these observations, interesting though they are, would not in themselves have justi­ fied a symposium. It seemed, however, useful to examine the new results from a wider perspective and to attempt to relate them to present-day knowledge of iron metabolism in general its physiology, its pathology, and therapeutic aspects. The success of a scientific symposium depends on the concep­ tion of the programme and the selection of the participants.