From family trees written in early American bibles to birther conspiracy theories, genealogy has always mattered in the United States, whether for taking stock of kin when organizing a family reunion or drawing on membership—by blood or other means—to claim rights to land, inheritances, and more. And since the advent of DNA kits that purportedly trace genealogical relations through genetics, millions of people have used them to learn about their medical histories, biological parentage, and ethnic background.  A Nation of Descendants traces Americans' fascination with tracking family lineage through three centuries. Francesca Morgan examines how specific groups throughout history grappled with finding and recording their forebears, focusing on Anglo-American white, Mormon, African American, Jewish, and Native American people. Morgan also describes how individuals and researchers use genealogy for personal and scholarly purposes, and she explores how local businesspeople, companies like Ancestry.com, and Henry Louis Gates Jr.'s Finding Your Roots series powered the commercialization and commodification of genealogy.