While their importance has been fully recognised and extensively studied in early modern Britain and in the Victorian period, the long eighteenth century has been too often presented as a black hole regarding genealogy. Enlightened values and urban sociability have been presented as inimical to the praise of ancestry and birth. In contrast, however, various studies on the continental or in the American colonies, have shed light on the many uses of genealogies, even beyond the landed elite. Whether it be in the publishing industry, in the urban corporations, in the scientific discourses, genealogy was used, not only as a resilient social practice, but also as a form of reasoning, a language and a tool to include newcomers, organise scientific and historical knowledge or to express various emotions. This volume aims to reconsider the flexibility of genealogical practices and their perpetual reconfiguration to meet renewed expectations in the period. Far from slowly vanishing under the blows of rationalism that would have delegitimized an ancient world based on various forms of hereditary determinism, the different contributions to this collective work demonstrate that genealogy is a pervasive tool to make sense of a fast-changing society.