"For too long a picture of the young Calvin's theology has been only partially available in English, with the result that key moments in the development of his reforming vision have been obscured. David Noe's crisp and complete translation of Calvin's first publication after his arrival in Geneva makes the full scope of Calvin's early reforming priorities accessible and so illuminates for English readers the emergence of central themes in Calvin's religious thought between the writing of the first (1536) and second (1539) editions of the Institutes. In this treatise, consisting of two open letters published in March 1537, Calvin for the first time openly criticizes the moderate French evangelical reform movement of which he had recently been a part. He intensifies concerns with idolatry, more aggressively attacks the Mass, and distinguishes the respective duties of laity and those holding church office to conform outer behavior to their reformed religious convictions when living as religious minorities. Read together, these two letters stand as Calvin's earliest public declaration of an emerging sense of his professional obligations as an office holder in a reformed church shaped by the radical evangelicalism of his recent but from this point on abiding associates, Guillaume Farel and Pierre Viret. This translation will serve, among other things, as an excellent classroom resource for unpacking the emergence of the distinctively Calvinist concern with the ethics of religious dissimulation and the potentially polluting effects of ceremonies judged to be illicit—matters that reflect the growing centrality of the glory of God and an increasing fascination with the complexities of human nature in both his theology and his work as church reformer." — Barbara Pitkin, Senior Lecturer of Religious Studies, Stanford, and editor of the Sixteenth Century Journal