Zhengzhi 鄭志 "A treatise on Zheng Xuan" is a philosophical text written during the Wei period 曹魏 (220-265) by Zheng Xiaotong 鄭小同 (c. 193- after 258), courtesy name Zizhen 子真, who was a grandson (or son) of the great Confucian master Zheng Xuan 鄭玄 (127-200) from the Later Han period 後漢 (25-220 CE).
Zheng Xiaotong hailed from Gaomi 高密, Shandong, and was a palace attendant (shizhong 侍中) during the reign of Cao Mao 曹髦 (r. 254-260 CE). When Sima Zhao 司馬昭 (211-265) took steps into the direction of usurping the throne of the Wei empire, he had Zheng Xiaotong poisoned. Zheng's disciples, shocked by the murder of their master, compiled an 8-juan long book in which the teachings of Zheng Xiaotong and his father were laid down in a question-and-answer pattern. They also produced a similar book called Zhengji 鄭記, with a length of 6 juan.
The descendants of Zheng Xiaotong later revised these texts and created a book Zhengzhi with a length of 11 juan that is recorded in the imperial bibliography Jingjizhi 經籍志 in the official dynastic history Suishu 隋書, but under the name of Zheng Xiaotong.
The book was lost during the Song period 宋 (960-1279), but a fragmentary version of 3 juan has survived. During the compilation of the imperial series Siku quanshu 四庫全書 the compilers combed ancient writings for fragments of the Zhengzhi and Zhengji that they assembled in an appendix (Buyi 補遺) to the text.
Apart from the Siku quanshu, other series also include the Zhengzhi, namely Zhengxue wuzhong 鄭學五種, Zhengxue shiba zhong 鄭學十八種, Gaomi yishu 高密遺書 and Juzhenban congshu 聚珍版叢書. A critical edition called Zhengzhi shuzheng 鄭志疏證 was written by the late Qing-period 清 (1644-1911) scholar Pi Xirui 皮錫瑞 (1850-1908).