In 1772, during the reign of Emperor Qianlong, Zhu Yun, the Education Commissioner of Anhui, submitted a memorial to the emperor requesting the reorganization of the Yongle Encyclopedia to gather more reference materials. Emperor Qianlong strongly supported this initiative and subsequently issued an order to collect books from across the empire, encouraging the populace to contribute their family collections. The emperor also named this new monumental work the Complete Library of the Four Treasuries. From this, it is evident that the Complete Library of the Four Treasuries was compiled based on the Yongle Encyclopedia, and the reorganization of the Yongle Encyclopedia became the reason the Complete Library of the Four Treasuries could be produced.
Once the imperial edict was issued, preparations began across the country, starting with the collection of books. From 1772 onward, the Qing government gathered a total of 12,237 titles, with Jiangsu contributing 4,808 and Zhejiang 4,600, ranking among the highest nationwide; some private book collectors, such as Ma Yu, Bao Shigong, and Wang Qishu, also donated their collections. The book collection effort was not declared complete until 1778, and Emperor Qianlong was very satisfied with the results, establishing a reward policy: those who contributed 500 titles received a copy of the Complete Collection of Ancient and Modern Books, while those contributing 100 titles received a copy of the Peiwen Yunfu; additionally, for any donor of 100 titles, the emperor would select the finest book, write encouraging remarks on it as a sign of favor, and the names of all contributors were recorded in a merit register.
After the book collection work was completed, the process of organizing and categorizing the books began. The Siku Quanshu (Complete Library of the Four Treasuries) not only included content from the Yongle Encyclopedia but also comprised books from the imperial library; works compiled by the Qing government itself, including some writings by emperors; books presented as tribute by provincial governments; books collected from the common people; and popular folk books. The civil officials responsible for compilation screened all the books, and those approved were divided into three categories. The first category consisted of masterpieces that were not only to be included in the Siku Quanshu but also published separately for circulation among the people. The second category included books that could be entered into the Siku Quanshu but did not meet the conditions for separate publication. The third category comprised books that could neither be included in the Siku Quanshu nor published separately, with only their titles preserved in the General Catalog of the Siku Quanshu. For the first two categories of eligible books, the civil officials had to carefully select the best version, as each book had many different editions. Once the chosen version was determined, the officials would polish and refine it. First, lower-level officials would revise the content, correcting typos, fixing grammatical errors, or deciding whether to delete or replace inappropriate words. These changes were written on slips of paper, inserted at the corresponding places in the book, and submitted to higher authorities for review. If the higher-level officials agreed with certain modifications, they would make the changes in the book using cinnabar brushes; if unsatisfied, they would leave them unchanged. The book was then presented to the highest-level official, who would make an overall judgment on the appropriateness of the revisions. If necessary, the senior official could overrule the decisions of the mid-level officials and adopt the revisions of the junior officials instead. In short, after undergoing three rounds of revision and review, the book was finally submitted to the emperor for inspection. If the emperor approved, the revisions for that book were finalized.
Next, the revised books had to be recopied by hand, which, despite sounding simple, was a physically demanding task. When selecting scribes, great care was taken to recruit only those with neat and beautiful handwriting. During recruitment, candidates were usually asked to write a few lines on the spot to assess their penmanship, with the best being chosen. Each scribe had a daily quota of 1,000 characters, amounting to 330,000 characters per year and 1.8 million over five years. If a scribe completed 2 million characters within five years, the imperial court would reward them with an official position. The highest rank was a subprefectural magistrate, the second rank (for completing 1.65 million characters in five years) was an assistant subprefectural magistrate, the third rank was a county deputy magistrate, and the fourth rank was a registrar. The transcription of the Complete Library of the Four Treasuries ultimately recruited 3,826 scribes, with up to 600 people copying daily at the peak, producing over 600,000 characters each day—a truly massive undertaking.
The final step of compilation was proofreading, which was extremely rigorous; the Qing government established specific reward and punishment regulations listing many possible types of errors, each with corresponding penalties. Proofreading had to be done twice—initial proofreading and re-proofreading—after which the chief supervisor would randomly select a few volumes from the corrected books for review, and only when no further errors were found would they be allowed to proceed to binding. It can be said that every official involved in the proofreading process had to be extremely meticulous, as they bore the greatest responsibility.
While compiling the Siku Quanshu (Complete Library of the Four Treasuries), the Qing court also produced the Siku Quanshu Huiyao (Essentials of the Four Treasuries), the Siku Quanshu Zongmu (General Catalog of the Four Treasuries), the Siku Quanshu Jianming Mulu (Concise Catalog of the Four Treasuries), the Siku Quanshu Kaozheng (Textual Criticisms of the Four Treasuries), and the Wuying Dian Juzhenban Congshu (Collectanea of Movable-Type Editions from the Hall of Military Glory), which can be considered derivative works of the Siku Quanshu.
The Complete Library of the Four Treasuries consists of 4 sections, 44 categories, and 66 subcategories. Among the four sections—Classics, History, Philosophy, and Literature—the Classics section has 10 categories and 9 subcategories; the History section has 15 categories and 27 subcategories; the Philosophy section has 14 categories and 25 subcategories; and the Literature section has 5 categories and 5 subcategories. The Complete Library of the Four Treasuries covers a very broad range, but during its compilation, many books containing anti-Qing sentiments were destroyed by the Qing government, and even those not destroyed were heavily altered, leaving later generations unable to know the true content. Moreover, the Qing dynasty did not value Western scientific technology, so many scientific and technical works were not included in the Complete Library of the Four Treasuries, which also reveals the Qing government's stubbornness and shortsightedness.