The Yongle da dian 永樂大典, or Yongle Encyclopedia, stands out as one of the most extensive attempts in world history to capture the entirety of human knowledge in book form. The 41 volumes digitized here represent the complete holdings for this title in the Asian Division of the Library of Congress. Although this number may represent only a small fraction of the whole encyclopedia, it is nevertheless the largest assemblage of Yongle specimens in a collection outside Asia.

This massive work was compiled between 1403 and 1408 under an edict of the third emperor of the Ming dynasty, Zhu Di, known by the reign name of Yongle 永樂 (r. 1402-1424). Incorporating content from many earlier publications, upon completion it encompassed 22,937 sections (juan 卷) containing some 370,000,000 characters. It also included an index comprising 60 sections, bound together into a total of 11,095 volumes (ce 册).

The encyclopedia represented an ambitious endeavor to record all forms of knowledge known to Chinese civilization at the time of Yongle's reign. It covered a diverse array of subjects that included Confucian classics, history, geography, philosophy, literature, science, art, statecraft, religion, and divination. The topics were arranged according to the order of the rhymes of the keywords found in the early Ming-period dictionary called Hong wu zheng yun 洪武正韵 (“Standard Rhymes of the Reign of Hongwu”).

A duplicate of the entire manuscript was produced between 1562 and 1567 during the reigns of the Jiajing 嘉靖 emperor (r. 1521-1567) and the Longqing 隆慶 emperor (r. 1567-1572). The original edition was later totally lost. Today only 420 volumes are known to exist, accounting for just four per cent of the complete set of the duplicate edition. These exceptionally rare books are distributed among more than 30 library and private collections around the world. Of these, the Library of Congress holds 41 unique, inconsecutive volumes.

Acquired during the early 20th century via purchase and donation, the Library’s Yongle volumes mirror the vast range of topics covered in the entire encyclopedia set: from biographies of emperors and eminent people to bronzes and inscriptions from dynasties prior to the Song (to 960); from drinking customs and wine rituals to local histories and maps from local gazetteers; and from divinatory trigrams, philosophical works, official reports, and treatises on gerontology to ethnic tribal groups, rare Chinese characters, and costume etiquette guidelines observed by government officials.

The compilers of the Yongle Encyclopedia incorporated content from earlier books produced throughout China, many of which disappeared over the ensuing centuries. As a result, the existing Yongle volumes are now the only source for studying certain forms of knowledge found in those lost texts that predate the early 15th century.