Constantin Fasolt's interest is focused on the historical background behind the structures of authority that governed the European and American worlds from the eighteenth until the twentieth century. His research deals with the origin and significance of modern historical and political thought. His teaching covers European intellectual history from the thirteenth to the seventeenth century, especially in Germany and France, with occasional glances further back in time. He has written books on late medieval theories of constitutional government as carried forward by the conciliar movement (Council and Hierarchy) and the significance of the early modern turn to history (The Limits of History). He is also general editor of New Perspectives on the Past, a series of interdisciplinary monographs on fundamental aspects of history published by Blackwell, Oxford.