) It is easy to appreciate from this why any 'communication science' has, necessarily, to be constructed from several different bodies of theory and evidence, drawn from several of the traditional 'disciplines' (especially sociology and psychology in the earlier days, but now also economics, history and literary and film studies). In this respect, the deepest and most enduring divisions separate interpersonal from mass communication, cultural from behavioural concerns, and institutional and historical perspectives from those which are cultural or behavioural. Putting the matter simply, there are essentially three main alternative approaches: the structural, the behavioural and the cultural.