The "Daoist Teachings of Zhong and Lu" (DTZL) recorded the daoist transmissions from Zhongli Quan to Lu Dongbin in a questions and answers format. The earliest historical record of this text can be found in the Northern Song Dynasty, in "Xuan He Shu Pu" volume 19 stated that Lu Dongbin was a disciple of Zhongli Quan and "there exits books of their dialogue and poems etc", the "dialogue" should be referring to this classic. The "Dao Shu" In the Song dynasty has collected this classic and called it "Collection of Daoist Transmissions". The 14th to 16th chapters of the "10 books on Cultivation" in the Doaist Canon, "Collection of Ancient and Modern Books" (Gu Jin Tu Shu Ji Cheng) and "Essentials of Daoist Canon" had also a copy of this classic.
"Daoist Teachings of Zhong and Lu" consists of the questions and answers between the two ancestors on the 18 specialized topics in cultivation ( "On true Immortals", "On Great Dao", "On Heaven and Earth", "On the Sun and the Moon", On Four Seasons", "On Five Elements", "On Water and Fire", "On Dragon and Tiger", "On Cinnabar and Medicine", "On lead and mercury", "On Extraction and Deposition", "On River Car", "On Restorative Cinnabar", "On refining the form", "On returning to the origin", "On internal viewing", "On Demonic Obstacles", "On verifications"). The book fleshed out the concepts clearly, revealed the different layers in each topic and it is full of wonderful discussions. This book had revealed to the world previously closely guarded daoist secrets. It is not an exaggeration to call this book the most important classic of the five ancestors and the seven sages and all the saints that followed them. DTZL is a more comprehensive discussion of the dandao of Zhong and Lu than any other publicly available classics.
To get to know the Zhong and Lu dandao better, the 18 topics of DTZL can be divided into 6 sections.
1. The Purpose. The goal of Zhong and Lu dandao is to become an immortal through cultivations. So what is an immortal? How to cultivate it? The answer is in "On true Immortals".
2. The Theory. Dandao is the fruit of the fusion between the great dao and the daoist culture. So how can we understand dandao from the point of view of the great Dao? The answer is in "On Great Dao".
3. The Theory from Yijing. Dandao culture was built on the backdrop of the idea "Heaven and Man become one". The "Heaven" in this idea consist of at least two levels of meaning. The "pre-heaven" (xiantian) stage of the universe and human, these had all been incorporated in the theory of "Zhou Yi". Secondly, how can we get to know the laws of the Yijing from observations of the circulation between of the heaven and earth, the movement of the Sun and the moon and the transitions between the 4 seasons and use these observations to help us understand the practical aspects of dandao. The different stages of the process in "Heaven and Man become one" are method of earth, method of heaven and method of Dao and they are explained in "On Heaven and Earth", "On the Sun and Moon" and "On the four seasons".
4. The theory of alchemy. The main idea in dandao is the theory of creation and rebirth, i.e. the creation of embryo from yin and yang, the embryo is nurtured until rebirth is possible. "Dao give birth to One, One gives birth to Two, Two gives birth to Three, Three gives birth to the ten thousands things". Creation is not possible without Yin and Yang. Yin and Yang is from "One", then where does "One" comes from? See "On the five elements". And how does "One" gives birth to Yin and Yang? See "On Water and Fire". How does Yin and Yang give births to the yang within yin and the yin within yang ? See "On Dragon and Tiger". How does Yin and Yang give birth to "Three", the embryo? And how do we nurture the Embryo ? See "On Cinnabar and Medicine". And how about the yin and yang in the embryo? See "On Lead and Mercury".
5. The theory on the cultivation method. Cultivation methods follow the laws of the nature, the theory in Yijing and the circulation between heaven and earth. How does one get the yin and yang, and how do we use the yin and yang? See "On extraction and deposition". How do we make the ying and yang follows the rise and fall (circulation) between the heaven and earth ? See "On River Car". How does one refine the quality and increase the volume of Yin and Yang? See "On restorative cinnabar". How does one cleanse the body with Yin and Yang? See "On Refining the form". How does one achieve transcension? See "On returning to the Origin". How does one see the process? See "On internal viewing". How does one overcome psychological obstacles? See "On demonic obstacles. The 10 methods and 45 segments of Ling Bao Bi Fa are precisely the practical methods to complement these theory.
6. On verifications. Since one has the methods, so we should also have verifications of the methods. To know the verifications in each stage, see "On Verifications". How does one assess the result and the achieved level of the immortality? See "On true immortals". How does one understand the great dao through cultivation ? See "On the Great Dao".
Looking at the content of DTZL, we can see that Ancestors Zhongli and Lu were standing and teaching us at a level unimaginable to mortals, they taught us true neidan and true methods, they told us that there are 5 levels of immortals: ghost immortal, human immortal, terrestrial immortal, shen immortal, celestial immortals. There are three levels of cultivation, minor cultivation, medium cultivation and great cultivation. Minor cultivation can grant one human immortal status, to live well and healthy on earth ; medium cultivation method can grant one terrestrial immortal status, to enjoy longevity; great cultivation method can grant one the shen immortal, celestial immortal status, to transcend from the material world. The method of neidan came from the great Dao, it states that the human body is a universe in itself, that's why one needs to imitate the circulation of the heaven and earth, the conversion of the 5 elements, the interactions of the sun and the moon in the body. To extract the Xiantian yang from the kidney water as the ingredients of dan, to mate the true yin and true yang, to mix and merge them, to circulate in the 3 fields, using yang to cook the yin and use the yin to refine the yang. By conversion of essence to qi, qi to shen, shen to the void and refine the void to Dao, then the golden dan can be formed and the yang shen can transcend. Jump out of the gate of heaven into the world of the three pure ones. The classic had detailed the 12 levels of internal refinement methods, they are Pairing the Ying and Yang number one, Collection and Dispersion of Water and Fire number two, The Mating of Dragon and Tiger number three, Burning and cooking the cinnabar medicine number four, The golden sphere flying up form the side number five, The jade liquid restorative cinnabar number six, the jade liquid refinement of the form number seven, the golden liquid restorative cinnabar number eight, the golden liquid refinement of the form number nine, returning to the origin to refine the qi number ten, internal viewing number eleven, transcension and subdivide number twelve. Combining sixth and seventh into one method, and the eighth and ninth into one method, reducing the twelve methods into ten, this is Ling Bao Bi Fa.
DTZL has established the venerable position of Zhong and Lu dandao: it inherited from the three pure ones and bequeath this treasure to the mortals in next one thousand year. It is the pinnacle achievement of the ancient daoist tradition; it wakes up the internal shen and ling of man and connect them to the external space and time. It is a comprehensive system of dandao cultivation, it revealed to the world the extraordinary wisdom of the daoist tradition and give people a glimpse of it's effective health and wellness method.
Therefore when we read DTZL, we need to ourselves in between the heaven and earth, time and space, to view and think about them from mutiple angles, the corporeal and concrete, the corporeal and formless and the incorporeal and formless. To see how can "heaven" and "man" become one? How does the "heaven" and "man" correspond to each other? What is being merged from "heaven" and "man" ? etc ..etc...