The c. 350 BCE Neiye 內業 or Inward Training is the oldest Chinese received text describing Daoist breath meditation techniques and qi circulation. After the Guanzi, a political and philosophical compendium, included the Neiye around the 2nd century BCE, it was seldom mentioned by Chinese scholars until the 20th century, when it was reevaluated as a "proto-Daoist" text that clearly influenced the Daode jing, Zhuangzi, and other classics. Neiye traditions also influenced Chinese thought and culture. For instance, it had the first references to cultivating the life forces jing "essence", qi "vital energy", and shen "spirit", which later became a fundamental concept in Daoist Neidan "internal alchemy", as well as the Three Treasures in traditional Chinese medicine.
The sinologist A. C. Graham regards the Neiye as "possibly the oldest 'mystical' text in China" (1989: 100). The professor of religious studies Harold D. Roth describes it as "a manual on the theory and practice of meditation that contains the earliest references to breath control and the earliest discussion of the physiological basis of self-cultivation in the Chinese tradition" (1991: 611–2), and perhaps the oldest extant text of Daoism (1994: 37).
The title is a compound of two common Chinese words: nèi 内 meaning "inside; inner; internal" and yè 業 "work; deed; achievement; production".
In ancient Old Chinese that was used when the Neiye was compiled, the two titular component words had complex meanings. Bernhard Karlgren's classic Grammata Serica Recensa dictionary translates nèi 內 as "enter; to bring in, to present; take to heart"; and says the early characters for yè 業 depicted a "horizontal board of a bell stand or frame", which was used as a phonetic loan character for "initiate; work; action; deed; profession; fortune, inheritance; strong; terrible" (1957: 695e, 640a)
While many English-language authors transliterate the 內業 title as Neiye or Nei-yeh, some translate it as:
The Workings of the Inner (Riegel 1978)
Inner Workings (Rickett 1985)
Operation of the Inner (Harper 1987)
Inner Cultivation or Inner Development (Kirkland 1997, 2008)
Inward Training (Graham 1989, Roth 1999)
Inner Training (Campany 2005)
The Inner Enterprise (Eno 2005)
A.