Running through the papers collected here is the concern to try and understand the reasons which people thought they had for acting in a certain way, and - not always the same thing - the reasons which they expressed for what they were doing. The book's first section focuses on the theories of government in the late medieval Church, especially the ideas of conciliarism; the second is concerned with the study of medieval guild and city organisation and politics, looking at the communal movement and at the impact of Christianity on the development of republican ideas. In the papers in the final part, Professor Black takes a comparative approach, setting the political thought and traditions of the Islamic world, in particular, alongside those of Western Europe as part of an attempt to understand the origins of the modern state: to know why this emerged in Europe, he argues, it is necessary to ask why it did not develop elsewhere and it is intellectual and cultural factors which provide the most obvious differentiating features.