In this scholarly, limpidly written work, Rubin (The Mother Mirror, 1984; The New Suburban Woman, 1982) recounts the story of Spain's greatest queen and the impact of her reign on her country and the world. The marriage of Isabella of Castile and Prince Ferdinand of Aragon (1469), more than any other event, caused the creation of the Spanish state by merging Spain's two main Christian kingdoms. Rubin demonstrates that Isabella's unique personality left a pervasive mark on the nascent Spanish society. Isabella's devout Catholicism led her to embrace religious fanatics like her confessor Cisneros, and resulted in the completion of the reconquista (the conquest of Moorish Spain), the expulsion of the Jews and Moors from Spain, and the institution of the uniquely repressive and cruel Spanish Inquisition (Rubin speculates, without much evidence, that Isabella suffered from a troubled conscience about these excesses). The author also shows how Isabella's faith motivated her to support Columbus's voyages of discovery (she saw his explorations principally as an opportunity to win new souls to Christ, and Rubin relies on primary sources to illustrate Isabella's misgivings at Columbus's frank exploitation of the natives). Rubin also explains the relationship between Isabella's personal tragedies and European politics--the marriage of her daughters Catherine and Juana had important historic consequences but both ended in tragedy. While the author demonstrates the critical importance of Isabella's reign for the Spain that emerged from it, she does not succeed in making a case for Isabella as a ``Renaissance queen'': Isabella united and strengthened Spain but left it intellectually hobbled and dominated by the Church, and less culturally diverse and tolerant than before. Nonetheless, Rubin succeeds admirably in recounting the accomplishments of one of European history's greatest monarchs. A first-rate exposition.