This reference work provides a comprehensive, chronological record of every officially recognized pope and antipope in the history of the Roman Catholic Church. The authors, J. N. D. Kelly and Michael Walsh, utilize historical records and ecclesiastical archives to document the lineage, social origins, and administrative activities of each pontiff from St. Peter to the modern era. The text serves as a scholarly resource for understanding the evolution of the papacy through individual biographical accounts.

Scholars and historians frequently cite this dictionary as a foundational reference text for its meticulous attention to detail and chronological accuracy. Readers often note the academic density of the prose, which is designed for researchers and students seeking precise historical data.