This volume investigates the evolution of military tactics, weaponry, and strategic organization in Western Europe between 1278 and 1485. Sir Charles Oman, a distinguished historian of the late 19th and early 20th centuries, utilizes primary source chronicles and administrative records to trace the decline of feudal cavalry and the rise of infantry-based armies. The work argues that this period represents a critical transition in the art of war, marked by the increasing professionalization of soldiers and the integration of gunpowder artillery into field operations.

Historians recognize this work as a foundational text in the study of medieval military history, despite its age. Readers frequently note the dense, academic prose and the author's reliance on traditional narrative history methods common to the early 20th century.