The subject of interdisciplinarity concerns the philosophy and the history of science in a twofold way: on the one hand the emergence, the development, and the mutual relationships between disciplines are, of course, one of the central subjects of research in the history of science; on the other hand philosophy and history of science are fields that are themselves of an interdisciplinary nature. In fact, these two aspects are also closely related to each other, as viewing philosophy and history of science as forerunners of an emerging interdisciplinary field may also serve to emphasize the as yet immature character of our understanding of the phenomenon of interdisciplinarity. A Festschrift dedicated to Robert S. Cohen and his interests in the inseparable bonds between the philosophy and history of science provides a natural occasion to deal with both of these aspects: part one of the following essay therefore discusses some features of the development of historical epistemology as an interdisciplinary field, while part two addresses the new technological conditions under which this development takes place today, including some sidelights on the impact of these conditions on the future of interdisciplinary research in general.²