The Dutch Catholic priest Frits van der Meer (1904–1994) was an internationally renowned scholar of art history and professor at the Catholic University in Nijmegen, the Netherlands. He published important studies on St. Augustine, Christian archeology and iconography, many of which were translated into English, French and German. Especially his Atlas of Western Civilization (1954) and Atlas of the Early Christian World (1958) were influential. While he was innovative in his scholarly work, he remained loyal to the old Catholic tradition, which he defended with conviction in the cultural upheaval in the 1960s and 1970s. He destroyed his personal archive, but the 135 letters that he sent to his sister Bertha, a nun in the contemplative order of the Discalced Carmelites, have been preserved. They offer an intimate view of his inner life, social and intellectual networks, theological and cultural views, and his travels. These letters are abundantly annotated and preceded by an extensive biography of the two protagonists.