"One of the significant approaches to the problem of reducing international tensions and thus liberating forces for economic and social development has been the phenomenal increase in recent years in international exchanges. These have been defined in the Unesco Handbook of International Exchanges as "the movement of persons, materials and information across frontiers in such a way as to communicate ideas and knowledge by word or image". The notion of exchange, it goes on, 'împlies some degree of reciprocity, in the sense that there are two or more partners in the process and that they have a more or less mutual effect on each other, but it does not necessarily imply an exact head-to-head accounting of persons sent and received". The magnitude of exchange activity is also indicated in this publication which provides information on the activities of 295 international organizations and over 4, 750 governmental and non-governmental agencies and institutions. It also lists no fewer than 4, 600 bilateral and multilateral agreements. While these agreements are primarily the concern of the nations themselves, Unesco and other international organizations can make an important contribution to the developing strategy for surmounting the obstacles to international understanding and co-operation. The present publication attempts to describe both the needs and the difficulties in the development of cultural co-operation as well as Unesco's efforts in this field." (Introduction)