This book explains how all persons with Western European ancestry are related through a Unifying Ancestry. The author presents the knowledge metrics needed to derive the best representation for a Unifying Ancestry. The book uses example lineages to historically notable persons including relationships to U.S. Presidents, royal families, actors, and singers in order to demonstrate these points. This third edition is based upon expanded data, applying the algorithms to validate the Unifying Ancestry to a 348,844-person Research Genealogy. The author successfully demonstrates that a Unifying Ancestry with 38,533 persons is sufficient to identify familial relationships between Western Europeans. In addition, this book: Provides algorithms to evaluate properties of genealogies for a variety of factors Utilizes the Unifying Ancestry CoreGen3 workbench analysis program enabling readers to reproduce the presented examples Presents methods to build a complete genealogy and identifies familial relationships between historical figures.