O'Brien's focus here is on the manuscript vital records and tombstones of Trinity Church and St. Paul's Chapel and their churchyards in the Lower Broadway section of Manhattan. In the first half of the volume O'Brien takes the reader on a "tour" of the two churches, stopping at a tombstone here or referring to a record there in order to elaborate about someone of Irish descent from his vast study of Irish American history and genealogy. The second part of the book consists of a variety of verbatim transcriptions copied from the records of Trinity and St. Paul's, as well as other sources, and referring to several thousand individuals. Included are tombstone inscriptions, marriages, baptisms, wills, letters of administration, deeds and conveyances pertaining to Irish Americans.