The thirteenth century saw such a proliferation of new encyclopedic texts that more than one scholar has called it the “century of the encyclopedias.” Variously referred to as a speculum, thesaurus, or imago mundi—the term encyclopedia was not commonly applied to such books until the eighteenth century—these texts were organized in such a way that a reader could easily locate a collection of authoritative statements on any given topic. Because they reproduced, rather than simply summarized, parts of prior texts, these compilations became libraries in miniature. This study examines writings in Latin, Catalan, and French that are connected to the encyclopedic movement: Vincent of Beauvais's Speculum maius; Ramon Llull's Libre de meravelles, Arbor scientiae, and Arbre de filosofia d'amor; and Jean de Meun's continuation of the Roman de la Rose. It analyzes the order of knowledge in these challenging texts, describing the wide-ranging interests, textual practices—including commentary, compilation, and organization—and diverse discourses they absorb from preexisting classical, patristic, and medieval writing. The book demonstrates how these encyclopedias, like libraries, became “heterotopias” of knowledge—spaces where many possible ways of knowing are juxtaposed. The book shows how encyclopedists employed the same practices of figuration, narrative, and citation as poets and romanciers.