The rapid expansion of the early Islamic world is conventionally ascribed to a combination of perceptive military leadership and religious fervour. By looking at the administration and taxation which would be implemented by political rulers, Abd al-Aziz Duri demonstrates how these leaders were able to provide for growth, development and durability in a turbulent time, as well as efficient mechanisms for taxation and tax collection. Drawing on original research into the fiscal policies of this period, especially land tax and the tax on non-Muslim populations, Duri shows how different models evolved and renewed themselves. He examines the political systems that accompanied these fiscal regimes, and attitudes towards them. He also scrutinises the institutions which supported this remarkably coherent mode of governance, offering a new perspective on the relationship between politics and Islam in this formative period.

By looking at these early Islamic institutions, Duri makes the argument that due to persistence of such organization, from the early Muslim conquests and the later Umayyad era to the end of 'Abbasid rule, the leaders of the time can be seen to be particularly politically and organizationally skilled. Duri's work makes a major contribution to our understanding of how Islam established itself and flourished as a lasting major force in the development of world history.