This "Supplement to Genealogies in the Library of Congress" lists all genealogies in the Library of Congress that were catalogued between 1972 and 1976, showing acquisitions made by the Library in the five years since publication of the original two-volume Bibliography. Arranged alphabetically by family name, it adds several thousand works to the canon, clinching the Bibliography's position as the premier finding-aid in genealogy.

Previously published by Magna Carta, Baltimore. Published as a set by Genealogical Publishing with the two vols. of the Genealogies in the Library of Congress, and the two vols. of the Supplement. Set ISBN is 0806316691.