||The impact of the thinking of Lao Tzu as embedded in the text named after him, the Lao Tzu, on the inner alchemy of Taoism has been enormous. Its enormous influence is all the more identifiable in the case of Zhong and Lu, who are the two most outstanding figures in the entire history of Taoist inner alchemy. This study, intended to examine the extent to which the inner alchemy of Zhong-Lu has been influenced by the thinking of Lao Tzu, will concern itself mainly with how the former has inherited and further elaborated upon the latter. The thinking of Lao Tzu will, however, also be discussed in considerable detail in this study; as without a good understanding of how Lao Tzu himself thinks in the related areas, it is quite impossible for one to see clearly the impacts it has on Zhong-Lu. The thesis is composed of five chapters. The "Introduction", by tracing the evolution of the concept of Tao as revealed in archaeological findings and the ancient texts, is intended to depict the intellectual background against which the cosmology and ontology of Lao Tzu emerge. It is believed that they form the foundation of Zhong-Lu's views on life reconstitution and mental practice. Chapter Two, "The Tao and Te of Lao Tzu", consists of two sections. The first section is one on the Tao and is divided into four parts, namely, "The Meaning of Tao", "The Formation of the Cosmos", "The Opposite and the Backward", and "The Constant". In this section, the characteristics of what Lao Tzu calls the Tao are discussed, with special reference to the mystical and delicate relationship between being and non-being, and the rules that govern the proliferation of the myriad things. The second section is on the Te, which is also divided into four parts: "The Meaning of Te", "The Functions of the Substance", "The Wisdom", and "The Mystical Virtue". With these four parts together, the fact that the Te, as the manifestation of the Tao, can only be comprehended through observing its functions and putting them into practice, and be reached through employing the wisdom inherited in the mind is fully explored. Chapter Three, entitled "The Tao of Health Preservation of Lao Tzu", is composed of five sections, each discussing one of the five elements that has direct bearing on the formulation of Zhong-Lu's philosophy of inner alchemy. The five sections includes "Emptiness and Stillness", "Embracing Oneness", "Holding to Suppleness", "Embracing the Uncarved Block", and "Getting rid of Desires". Chapter Four, "The Impacts of Lao Tzu on the Inner Alchemy of Zhong-Lu", is the very chapter written specifically for the purpose of pinpointing how the legacy of Lao Tzu has made itself felt in Zhong-Lu's philosophy of inner alchemy. Dividing into two sections, this chapter approaches the issue from the perspective that sees Zhong-Lu's inner alchemy as program of both mental and physical practice. Each of these two sections is divided into three parts. In the section on "Mental Practice", it is argued that Zhong-Lu's theories of "The Mind of Having no Mind" and "The Emptiness, Stillness, and Non-Action" actually have their origins in Lao Tzu's ideas of mystery and non-action achieved through attaining emptiness and holding to stillness to the utmost, respectively. It is also argued in this section that Zhong-Lu's theory of "Eliminating Thoughts and Forgetting Emotions" is a further expansion of Lao Tzu's idea of mystery. On the other hand, the entire section on "Physical Practice" basically argues that Lao Tzu's cosmology is the foundation of Zhong-Lu's theories concerning physical practice. It is demonstrated in Part One of this section that the state of proliferation of air and fluid inside the human body as advocated by Zhong-Lu is to be achieved through practicing Lao Tzu's idea of carrying on one's backs the yin and embracing in one's arms the yang. In Part Two, it is argued that Zhong-Lu's theory of intermingling the dragon with the tiger is actually founded upon Lao Tzu's ideas of seeking the essence in the dim and dark and returning to one's root and destiny. In Part Three, it is illustrated that Zhong-Lu's theory of the immortal transcending its physical limitation and practicing morality widely on earth is indeed the elaboration of Lao Tzu's idea of giving the myriad things life yet claiming no possession. The "Conclusion" provides a summary of the above discussions that Lao Tzu's ideas regarding the cultivation of the mind and the nature serve as the precursor of Zhong-Lu's program of self-cultivation, which is both systematic and concrete. It is also pointed out there that while Lao Tzu's idea of returning to one's root and destiny has generated important insights into how reconstitution of life is to be achieved, Zhong-Lu's theory concerning how to become immortal is definitely the elaboration of Lao Tzu's idea of the constant.