Yan Kejun 嚴可均 (1762—1843), courtesy name Jingwen 景文, style Tieqiao 鐵橋, was a mid-Qing period 清 (1644-1911) scholar and book collector. He hailed from Wucheng 烏程 (modern Wuxing 吳興, Zhejiang) and obtained the juren degree in 1800. He became educational instructor (jiaoyu 教諭) in Jiande 建德, but soon left this post because of illness.
He was very interested in etymology and compiled, together with Yao Wentian 姚文田 (1758-1827), a long commentary on the Han period 漢 (206 BCE-220 CE) dictionary Shuowen jiezi 說文解字, the Shuowen changbian 說文長編, in which the authors discussed matters of astronomy, mathematics, geography, and biology. He also published Zhong Ding's 鍾鼎 draft on the Shuowen as Shuowen yishuo 說文翼說. Together with Ding Rong 丁溶 (1829-1879), he published the book Shijing 石經, a large compendium on ancient stone inscriptions. In 1808, the Jiaqing Emperor 嘉慶 (r. 1795-1820) established a group for the compilation of the collected writings of the Tang period 唐 (618-907), the projected Quantangwen 全唐文. Yan Kejun was very disappointed that he, as a private person, had not the chance to participate in this project, and thereupon directed his mind toward pre-Tang writings and began with the compilation of the book Quan shanggu Sandai Qin Han Sanguo Liuchao wen 全上古三代秦漢三國六朝文, the collected writings from oldest times until the founding of the Tang dynasty. This large collection includes the writings of more than 3,000 authors, to each of which Yan Kejun added a small biography, as well as text-critical comments on their writings. He also compiled fragments to all types of books and published the 1,200-juan long collection Silutang leiju 四錄堂類聚.
For his publications, he travelled a lot to acquire as much rare books as possible, and created a library of more than 20,000 juan. He was disappointed that he was not able to buy more of the excellent Song period 宋 (960-1279) prints. Yan Kejun compiled several catalogues that provide an insight into the holdings of the largest private libraries of his time, like the Shishantang mulu 世善堂書目, Tianyige mulu 天一閣書目, Wanjuanlou shumu 萬卷樓書目, Shixuelou shumu 世學樓書目 and Chuanshilou shumu 傳是樓書目. These catalogues even include rubbings of stone inscriptions as well as Buddhist and Daoist writings normally not considered as worth being recorded in bibliographies. Yan Kejun's own collected writings are called Shuowen shenglei 說文聲類 and Tieqiao mangao 鐵橋漫稿.