One of the most remarkable results of the arrival of Europeans in the New World may often be taken for granted: the emergence of the mestizo component in Latin American societies. The racial mixing that occurred in the Hispanic New World is the subject of this important study, which draws on a wide variety of historical, ethnographic, demographic, and biological sources to analyze processes of intermarriage, assimilation, and acculturation that continue in Latin America to the present day.

Mestizaje in Ibero-America sheds new light on miscegenation and acculturation: their different levels and proportions in particular periods and in rural and urban areas, and the role of Spanish, Indian, and African women in the historical process of biological fusion. Although racial and cultural mixing usually coincided, Esteva observes that mestizos were often assimilated into Indian or Spanish society during the early colonial period and that acculturation without miscegenation sometimes occurred.

He also shows that, contrary to the belief that "pure" Spanish blood was diluted in the New World, racial mixing and acculturation already existed in Iberia, facilitating its occurrence in America.