vi The intent, therefore, was to provide for a fresh and original review of all relevant topics and issues in the field, following a comprehensive and coherent programme. Such an ambitious goal could only be reached thanks to the unlimited collaboration of the lecturers: They were requested to produce nothing less than "freer, broader, speculative and personal "considerations of the subjects" they had to cover And so they did: their presentations unfolded a fantastic picture, a most fascinating and meaningful identification of the field, its present problems and trends. But participants at...