This biography investigates the political trajectory of Richard, third Duke of York, to determine how a loyal subject transitioned into the primary opposition against the regime of Henry VI. P. A. Johnson utilizes archival records and contemporary accounts to reconstruct the Duke's career, specifically examining his two tenures as Protector of England. The text argues that Richard's eventual claim to the throne in 1460 was the culmination of long-term political isolation rather than a sudden ambition.

Historians recognize this work as a foundational study for understanding the political complexities of the mid-fifteenth century. Readers frequently note the academic density of the prose, which provides a rigorous examination of the power dynamics between the monarchy and the nobility.