This work functions as a comprehensive repository of biographical data concerning individuals who have shaped the history of the British Isles. The Oxford University Press maintains this reference set, utilizing extensive archival research and contributions from historical scholars to document the lives of significant figures. It provides a standardized framework for historical inquiry, offering verified accounts of public and private lives across centuries of British development.

Experts and historians recognize this work as the definitive biographical reference for British history. Readers frequently note the academic density and rigorous fact-checking that characterize each entry within the collection.