The Daozang is not a book and it is not a Bible. It is the entire received scriptural literature of Taoism, about fifteen hundred titles, and its organising scheme is unlike that of any Western canon. The texts are divided into three caverns, dong, and the division is by source of revelation: Dongzhen for the Shangqing revelations of the fourth century, Dongxuan for the Lingbao scriptures, Dongshen for the Sanhuang tradition. Four supplements were added later, one of them for the Way of the Celestial Masters, whose texts were older than the scheme and did not fit it. The result is a catalogue that records the history of Taoist revelation in its own shape, and it also functioned as a curriculum: a priest's ordination rank determined which cavern's texts he was entitled to receive.
The contents are correspondingly various. Scripture proper, but also ritual manuals, alchemical treatises both laboratory and internal, hagiographies of immortals, medical and dietary works, talismanic diagrams, commentaries on the Tao Te Ching, and the liturgies for the salvation of the dead in which the Heavenly Worthy who Relieves Suffering is invoked. Because so much of early Chinese technical literature survives nowhere else, the Daozang is a primary source for the history of Chinese medicine, chemistry and printing as well as of religion.