The Esquer family originated in the Spanish Basque province of Navarra. The family gained prominence around the beginning of the eighteenth century in Mexico City and on the northwestern frontier of New Spain. The social aspirations, religious beliefs, and traditions that sailed with the family to the New World in the late seventeenth century typified the culture of New Spain. This made it possible for the family to quickly adapt to the norms of their new home in colonial Spain, and to forge bonds to enhance their social and economic status. Upon arrival in New Spain, the Esquer family wasted no time in arranging marriage alliances with local Spanish and Creole families. Such marriages brought the Esquer family into the fold of the socially elite, as evidenced by their genealogy. This book is a journey through the centuries that follows the Esquer family from their home region of Navarra, Spain, to the northwestern frontier of New Spain, and into the early years of the Mexican Republic (from 1550 to 1850). It is a genealogy that was created from civil and Catholic Church archival sources, primarily for the Spanish provinces of Sinaloa, Sonora, and Alta California. The book's purpose is to serve as a resource for those searching their family's roots in the above- named geographic areas. Much of what is recorded is focused in what are today the cities of Culiacán, Sinaloa, and Álamos, Sonora, Mexico. It also features members of the 1775-1776 Juan Bautista de Anza expedition to Alta California. The genealogy follows a narrative format and is grouped by generation through the eighth generation. Known children of the eighth generation are included but with less information. The book features documented life events, such as births, baptisms, marriages, deaths, and burials for more than 1,000 Esquer descendants, including spouses. Names of subjects, parents, spouses, witnesses, and godparents are included and indexed, and the source for each event is cited in a footnote.This current publication is a companion volume to the book, Esquer Family Chronicles, 1600-1800: From the Basque Country to the Northwestern Frontier of New Spain, originally written and published by Stella Cardoza in 2014 as a history of the Esquer family. An updated version is scheduled to be published in 2020.