Centred on a dozen texts in Spanish or Latin composed by Spaniards - both laymen and clergy - in the Spanish Netherlands as well as Spain, this study follows the debate during Philip II's reign concerning the principles, purposes and values - both secular and religious - relevant to rulers and to society at large. Part I examines three treatises produced in the Spanish Netherlands in the 1550s; Parts II and III respectively study works from the Kingdoms of Castile and the Crown of Aragon in the 1570s and 1580s; Part IV considers three Jesuit treatises of the 1590s. The resultant picture will interest those concerned with the intellectual, religious, social and political values of Philip II's Spain, whether as considered within its own boundaries or in the larger intellectual context of Western Europe.