A meticulously researched reference work that chronicles the lives and legacies of every pope from Saint Peter to Benedict XVI, including antipopes. Structured as a chronological series of biographical entries, the book offers a continuous narrative of the papacy’s evolution across nearly two millennia. Each entry provides a concise yet informative account of the pope’s background, ecclesiastical career, major actions during their pontificate, and the historical context in which they served.

Kelly’s approach blends theological insight with historical rigor, making the dictionary both accessible and authoritative. The entries illuminate the shifting role of the papacy in relation to secular power, doctrinal development, and internal Church reform. The volume also includes appendices on disputed figures such as Pope Joan, offering critical analysis of legendary and apocryphal claims.