The Celestial Master — tianshi dao, the Way of the Celestial Master — occupies a foundational and persistently contested position across the depth of the Daoist corpus as represented in this library. Livia Kohn’s Daoism Handbook provides the most sustained engagement, tracing the institution from its origins with Zhang Daoling in the late Han through its bifurcation into Southern and Northern branches, its absorption into the Three Caverns canonical scheme, and its reassertion of primacy during the Song-Yuan transformation. The term designates simultaneously a lineage title, a soteriological office, and an institutional form: the Celestial Master both governs the people and controls demons, inheriting a quasi-theocratic authority that distinguishes the movement from more inward-oriented traditions. Scholarly tension centers on the relationship between early Celestial Master institutions — registers, parishes, penitential petitions — and the reform impulses of figures like Lu Xiujing, who prescribed idealized practices against a landscape of what he regarded as deviation. The term further indexes debates about diffusion routes, lay organization, ordination hierarchy, and the movement’s capacity to absorb and legitimate newer ritual traditions, from Lingbao and Shangqing to the Thunder Rites of the Song. Depth-psychological relevance lies in the Celestial Master’s structural role as mediating authority between cosmic bureaucracy and embodied community — a psycho-spiritual economy of confession, healing, and covenant renewal.