Liu Xin 劉歆 (d. 23 CE), courtesy name Zijun 子駿, was a philosopher and historian during the late years of the Former Han period. Liu Xin later changed his name to Liu Xiu 劉秀, courtesy name Liu Yingshu 劉穎叔. He was a member of the imperial house and was the third son of the bibliographer and historian Liu Xiang 劉向.
Already in his youth he loved studing the ancient writings and accompanied his father in the imperial library. Liu Xin soon became an expert in all literary genres, from the Confucian Classics (Liuyi 六藝 "Six arts"), official biographies (zhuanji 傳記), the masters and philosophers (zhuzi 諸子), poetry and rhapsodies (shifu 詩賦), astronomical treatises (shushu 術數) and books on magic (fangji 方技).
When Emperor Ai 漢哀帝 (r. 7-1 BCE) mounted the throne, he took over the responsibility for the Five Classics (wujing 五經) in the library (with the concurrent post as commandant of the Capital Garrison, zhonglei xiaowei 中壘校尉), a task formerly entrusted to his father. Liu Xin compiled an annotated catalogue, the Qilüe 七略 , on the basis of his father's draft Bielu 別錄. He also wrote a commentary on the history Zuozhuan 左傳, a parallel to the Confucian Classic Chunqiu 春秋 "Spring and Autumn Annals".
He also suggested to the emperor to appoint erudites (boshi 博士) for the Zuozhuan, the Maoshi 毛詩 "Mao's Book of Songs", the Yili 逸禮 "Surviving rites" (i.e. Zhouli 周禮) and the old-text version of the Shangshu 古文尚書 "Book of Documents".
His unorthodox interpretation of the Classics instigated the hatred of Confucian scholars, especially those believing in the orthodoxy of the new-character texts (jinwenjing 今文經). In fear of being charged of rebellion he asked to be transferred to a local official post. The emperor thereupon appointed him to the governorship (taishou 太守) of several commanderies.
When Wang Mang 王莽 usurped the throne, a supporter of the old-text tradition, Liu Xin was appointed Preceptor of the State (guoshi 國師) and was given the title of marquis. In a memorial to the throne Liu Xin pointed out that the new-text classics were too short and often misleading, while the old-text classics could be trusted as the true Confucian writings. Zuo Qiuming 左丘明, for instance, the compiler of the Zuozhuan, was a contemporarian of Confucius 孔子, while the authors of the Gongyang 公羊 and Guliang 穀梁 commentaries lived centuries after Confucius and could not have known the truth.
His loyalty to Wang Mang went only so far as his "new" Xin dynasty 新 (8-22 CE) was stable. When the Red Eyebrows 赤眉 rebelled, Liu Xin participated in a plot against Wang Mang. Yet the plan was reveiled and Liu Xin suffered the death penalty.
The bibliography Qilüe is preserved in a short form in the bibliography Yiwenzhi 藝文志 in the official dynastic history Hanshu 漢書. The books of the imperial library were arranged according to seven types of writings: Compilations (ji 輯), Confucian Classics, masters and philosophers, poetry and rhapsodies, military treatises (bingshu 兵書), astronomical treatises and magical treatises. The first part is actually a kind of preface. The Qilüe lists 603 writers with books of a size of 13,219 juan.
Liu Xin had also written an astronomical treatise, the Santong lipu 三統歷譜. His other writings are lost, but the Ming-period 明 (1368-1644) scholar Zhang Tao 張濤 collected surviving fragements of his writings (Liu Zijun ji 劉子駿集) in his book Wei Han Liuchao baisan mingjia ji 魏漢六朝百三名家集.