Rudolf Steiner’s monographs on ›Mysticism‹ (1901/1924) and ›Christianity‹ (1902/1910/1925) mark a crucial phase in the genesis of anthroposophy; they document his transformation from philosopher and philologist into the mystic and esotericist of later years. Consequently, these texts are at the heart of ongoing academic controversy about the consistency of Steiner’s intellectual development and his relationship to Anglo-Indian Theosophy and traditional Christianity. The fifth volume presents these foundational texts of Anthroposophy for the first time in critical edition, thus providing a much needed textual basis for the discourse about Steiner and the validity and significance of his work.