Reading Illegitimacy in Early Iberian Literature presents illegitimacy as a fluid, creative, and negotiable concept in early literature which challenges society’s definition of what is acceptable. Through the medieval epic poems Cantar de Mio Cid and Mocedades de Rodrigo, the ballad tradition, Cervantes’s Novelas ejemplares, and Lope de Vega’s theatre, Geraldine Hazbun demonstrates that illegitimacy and legitimacy are interconnected and flexible categories defined in relation to marriage, sex, bodies, ethnicity, religion, lineage, and legacy. Both categories are subject to the uncertainties and freedoms of language and fiction and frequently constructed around axes of quantity and completeness. These literary texts, covering a range of illegitimate figures, some with an historical basis, demonstrate that truth, propriety, and standards of behaviour are not forged in the law code or the pulpit but in literature’s fluid system of producing meaning.