This volume, part of the *Mémoires* series, offers a concise yet thorough overview of Spain under the reign of the Catholic Monarchs. Drawing on contemporary sources, the author examines the political consolidation, religious reforms, and overseas expansion that defined the era of Ferdinand and Isabella. Readers will find analysis of the unification of Castile and Aragon, the completion of the Reconquista, the establishment of the Spanish Inquisition, and the early voyages that set the stage for Spain’s global empire. The work balances narrative history with illustrative maps and documents, making it a useful reference for anyone interested in the foundations of early modern Europe.