This fascinating publication studies the activities of the Spanish Royal Maritime Vaccination Expedition's introduction of the small pox vaccination to the New World, led by Dr. Francisco Xavier de Balmis y Berenguer. With a focus on Mexico and Guatemala, Smith's work illuminates a rich cultural, intellectual, and technical moment in the early 19th century. This piece serves as a crucial text for medical and colonial history as it recounts the most ambitious medical project conceived and carried out to its day.