This work is widely recognized as the preeminent textbook for Scots-Irish genealogy. This 2018 second edition is a massively expanded version of its 2005 predecessor. The new edition includes additional information on church records and landed estate papers, as well as new chapters looking at records relating to law and order, emigration, business and occupations, diaries and journals, and clubs and societies.

The work is divided into two main sections. The first section describes the sources for Scots-Irish ancestry, their significance, and where they may be found. The main categories covered here include church records, gravestone inscriptions, 17th-century records, 18th-century records, landed estate records, the Registry of Deeds, inheritance records, legal records, election records, military sources, newspapers and books, emigration records, education, charity and occupation records, business and occupational sources, society and club records, and personal records (diaries, journals, memoirs, etc.).

The second section consists of two large appendices. The first appendix lists, in summary format, the sources available for each parish in Ulster, while the second provides information on over 350 estate collections with relevant material from the pre-1800 period.

An historical essay highlights Ulster's establishment and the emigration from Ulster, especially in the 18th century. The author's Introduction contains valuable suggestions for beginning research on Ulster ancestors and cites other sources that can be helpful in uncovering information on a particular subject or geographical area.