This is a preface and excerpts from the Lingbao Essential Teachings, a foundational text of the Zhong-Lü alchemical school within Daoism. Authored by Zhongli Quan and transmitted to Lü Dongbin, it details alchemical principles, cosmology, and self-cultivation practices aimed at achieving immortality. The text draws on a compilation of earlier works, emphasizing the interplay of Yin and Yang, the importance of timing, and the refinement of internal energies. Its influence extended to later Daoist schools, solidifying its importance in the history of internal alchemy (Neidan). The preface highlights the author's discovery of the source material and his decision to share this knowledge widely.