Preservation is communication with the future. This requires constructing a context for interpreting historical records and archiving both the records and context for future use. Genealogies depend on the parsing of communications from the past that do not have an associated context. The solution is to mine the communications for relationships between information elements, construct a knowledge base, and evaluate the properties of Consistency, Correctness, Closure, Connectivity, Completeness, and Coherence. This book defines relevant metrics for genealogies and uses the results to define the properties of a complete genealogy. A complete genealogy will have three main sections: the immediate ancestors; links from the ancestors to a Unifying Ancestry for a national community; and links from the Unifying Ancestry to an Age of Progenitors. The result is a Genealogical History of the Modern World.