In the second half of the twentieth century, oral history has had a significant impact upon contemporary history as practised in many countries. While interviews with members of social and political elites have expanded the range of existing documentary sources, the most distinctive contribution of oral history is that it includes within the historical record the experiences and perspectives of groups of people who might otherwise have been 'hidden from history'. Although such people may in the past have been written about by social observers or in official documents, their own voices have only rarely been preserved -- usually in the form of personal papers or pieces of autobiographical writing. Through oral history interviews, working-class men and women, and members of cultural minorities, among others, have added their experiences to the historical record, and offered their own interpretations of history. Moreover, interviews have documented particular aspects of historical experience which tend to be missing from other sources, such as personal relations, domestic work or family life, and they have resonated with the subjective or personal meanings of lived experience.
0ral history has challenged the historical enterprise in other ways. Oral historians have had to develop skills required for the creation of recorded interviews, and to learn from different academic fields -- including sociology, anthropology, psychology and linguistics -- to better understand the narratives of memory. Most significantly, oral history is based on an active human relationship between historians and their sources, which can transform the practice of history in several ways. The narrator not only recalls the past but also asserts his or her interpretation of that past; and thus, in participatory oral history projects, the interviewee can be a historian as well as the source. Moreover, for some who practise it, oral history has gone beyond just making histories. In certain projects a primary aim has been the empowerment of individuals or social groups through the process of remembering and reinterpreting the past.