The Carthusian monks at San Martino began a series of decorative campaigns in the 1580s that continued until 1757, transforming the church of their monastery, the Certosa di San Martino, into a jewel of marble revetment, painting, and sculpture. The aesthetics of the church generate a jarring moral conflict: few religious orders honored the ideals of poverty and simplicity so ardently yet decorated so sumptuously. In this study, Nick Napoli explores the terms of this conflict and of how it sought resolution amidst the social and economic realities and the political and religious culture of early modern Naples. Napoli mines the documentary record of the decorative campaigns at San Martino, revealing the rich testimony it provides relating to both the monks’ and the artists’ expectations of how practice and payment should transpire. From these documents, the author delivers insight into the ethical and economic foundations of artistic practice in early modern Naples. The first English-language study of a key monument in Naples and the first to situate the complex within the cultural history of the city, The Ethics of Ornament in Early Modern Naples sheds new light on the Neapolitan baroque, industries of art in the age before capitalism, and the relation of art, architecture, and ornament.