Melissa Daggett's Eugène and Eulalie is an epic story of love, race, prosperity, and legal maneuvering. It chronicles for the first time in a comprehensive way the largely forgotten lives of Eulalie Mandeville, a free woman of color, and her white partner, Eugène Macarty. Mandeville and Macarty, both descendants of elite colonial families, began an interracial relationship in the 1790s that endured for more than half a century and produced five children. It also led to Mandeville's phenomenal rise to the pinnacle of wealth and success within the unique tripartite racial structure of nineteenth-century New Orleans.

Daggett uses the voluminous Nicolas Théodore Macarty et al. vs. Eulalie Mandeville f.w.c. (1848) court case to examine how an interracial relationship continued for more than fifty years despite onerous laws during the Spanish regime and the antebellum era that complicated such partnerships. She examines the origins of the Macarty and Mandeville families, revealing how they paralleled each other in Louisiana history and often intersected on social, military, economic, and political levels. Daggett also analyzes the struggles of the free people of color in both colonial Louisiana and early America and explores the ways slavery, manumission, and inheritance laws connected the two families. Above all, her work recovers the unique story of Eugène Macarty and Eulalie Mandeville, which has languished in the shadows of historical obscurity for generations.