This book was at first planned as a monograph on the nature of the caliphate at its foundation and during its earliest phase, before the establishment of Umayyad dynastic rule, with only a minimal discussion of the events and persons determining its evolution. The extreme distrust of most western historians with regard to the Muslim literary sources for the early age of Islam seemed to suggest a restriction of the inquiry to a few salient events whose reality, if not their interpretation, is not seriously disputed. As the research progressed, it became evident that such an approach would not do justice to the subject. The question of the caliphate is too intricately tied to much of the internal history of the early Muslim community to be discussed without a solid understanding of that history based on more than abstract speculation. Work with the narrative sources, both those that have been available to historians for a long time and others which have been published recently, made it plain that their wholesale rejection as late fiction is unjustified and that with a judicious use of them a much more reliable and accurate portrait of the period can be drawn than has so far been realized.

The introduction of large narrative sections into the presentation has, apart from substantially expanding the volume, inevitably changed the character of the book and produced a certain dichotomy which may at times obscure its basic purpose. Especially the detailed description of he fitna the Inter-Muslim War opening with the revolt against the third caliph and outlasting the reign of the fourth, may appear to have marginalized the discussion of the caliphate itself.