The Tangjian 唐鑒 "Mirror of the Tang dynasty" is a historical critique to the Tang period 唐 (618-907) written by the Song period 宋 (960-1279) scholar Fan Zuyu 范祖禹 (1041－1098) and commented by Lü Zuqian 呂祖謙 (1137－1181). The book itself is 12 juan "scrolls" long, including the commentary 24 juan.
Although it attracted a wide readership, it was also criticized for including the reign of Empress Wu 武則天 (r. 690-704) into the reign of Emperor Zhongzong 唐中宗 (r. 683-684, 705-709) instead of treating her reign as an own ruler.
There are small character prints from the Song and Yuan 元 (1279-1368) periods. The print from 1497 is included in the collectaneum Jinhua congshu 金華叢書.
Source: Li Xueqin 李學勤, Lü Wenyu 呂文鬰 (1996). Siku da cidian 四庫大辭典, vol. 1, p. 1517. Changchun: Jilin daxue chubanshe.