Since 1965 the Nobel Foundation sponsors, through grants from the Bank of Sweden Tercentenary Fund, Sym- posia on subjects which are considered to be of central scientific importance and for which new results of a special interest have been reached. The aim of these Symposia is to bring together, by personal invitation, a limited number of leading scientists from various countries to discuss the current research situation within the field and to define the most urgent problems to be solved. One of the most important fields in modern biome- dical research concerns the structure and function of...