An enormous amount of new knowledge on the molecular basis of various biological phenomena has emerged in the rapidly expanding field of bioscience. Since the frontiers in scientific research are difficult to define' the creation of new knowledge depends not only on new methods and concepts but also on interaction with other fields of research. The principles and methods of biophysics should be a rational language for discussion not only between scientists of the different disciplines of natural sciences' such as physics' mathematics' biochemistry' molecular biology and biotechnology' but also for medicine and social sciences as well. This is the general philosophy behind the organization of the Summer Schools organized by Rudjer Institute' Zagreb' Croatia and the Croatian Biophysical Society. The International Summer Schools on Biophysics have a very broad scope. This is in contrast to the other workshops or schools which are centred mainly on one topic or technique. The intention was to organize courses which provided advanced training at doctoral or postdoctoral level in biosciences. Therefore' the Schools essentially have a catalytic role and are complementary to' rather than competing with' activities of parallel national or international programmes.