This work investigates the structural evolution and functional mechanics of the military system in England following the Norman Conquest. C. Warren Hollister, a noted medievalist, utilizes primary source documentation and administrative records to analyze the transition from Anglo-Saxon fyrd systems to the feudal military obligations introduced by the Normans. The book argues that the military organization was not a static imposition but a complex adaptation of existing structures integrated with continental feudal practices.

Historians and medieval scholars frequently cite this text as a foundational study for understanding the administrative complexities of the Norman military apparatus. Readers often note the academic density of the prose, which provides a rigorous examination of institutional history for serious students of the period.