The art of letter writing certainly increased in importance in the eighteenth century and gained in literary respect as well. But from a pragmatic and communicative perspective, correspondence proved to be one of the critical tools in establishing a transnational, if not global community. Heretofore mostly ignored in this respect, the Jesuit Order emerged as a global player, sending missionaries to virtually all parts of the known world to spread the Gospel, to teach, and to convert. Most missionaries stayed in close contact with their superiors by means of letters, so this article begins with a close study of the huge letter collection compiled by Joseph Stöcklein, who translated letters from all over the world into German. The true purpose of this article, however, is the analysis of the large collection of letters composed by the Swiss Jesuit missionary Philipp Segesser, who closely communicated with his family back in Lucerne throughout his life, especially when he lived in Sonora (today northern Mexico and southern Arizona). These letters allow us to gain a good understanding of his personality, his emotional and intellectual growth, his relationship with the Jesuit Order at large, his family, and also of the condition of Jesuit efforts to convert the native population. His mostly completely intact corpus of letters provides an extraordinary opportunity to gain insight into personal perspectives regarding a global organization, the Jesuits, its relationship with the royal house of Spain, the condition in colonial Mexico, and the interaction between Europeans and native Americans. [ABSTRACT FROM AUTHOR]