Tang guoshi bu 唐國史補 "Supplement to the history of the Tang dynasty", short Guoshibu 國史補, is a collection of stories from the history of the early Tang period 唐 (618-907). It was written by the mid-Tang period scholar Li Zhao 李肇 (d. before 836), author of the statutory treatise Hanlinzhi 翰林志. The 3 juan "scrolls" long book contains 308 different stories of semi-historiographical character. Each chapter has a 5 characters long title, like Cui Hao jian Li Yong 崔顥見李邕 or Lu Shan ru xiong zi 魯山乳兄子. Of great importance are the stories about writers and poets, of whose life and writings a lot of information is provided. Li Zhao compiled this book as an imitation of a collection of biographies compiled by Liu Su 劉餗, the Guochao zhuanji 國朝傳記 "Biographies of Our dynasty". The Guoshi bu includes more than 100 biographies of early Tang period persons that supplemented information not found in official histories. Li Zhao explained that he only included reliable stories and refrained from recording phantastic tales, a genre that was very popular during his time. The result can therefore serve to add information on history, literature, administration and culture on the early Tang period.
The Tang guoshi bu is first mentioned in the imperial bibliography of the official dynastic history Xintangshu 新唐書, with a length of 3 juan, and the Song period 宋 (960-1279) bibliography Junzhai dushu zhi 郡齋讀書志 and the encyclopedia Wenxian tongkao 文獻通考, with a length of 2 juan (which might be a clerical error).
The most important editions are included in the reprint series Jindai mishu 津逮秘書, Xuejin taoyuan 學津討原, Siku quanshu 四庫全書, Biji xiaoshuo daguan 筆記小說大觀, Tangren shuohui 唐人說薈, Shuofu 說郛 and Tang-Song congshu 唐宋叢書. In the last two, the Tang guoshi bu is only one juan long. In 1957 the Shanghai guji press 上海古籍出版社出版 published a joint edition with the Yinhualu 因話錄 in the series Zhongguo wenxue cankao ziliao xiao congshu 中國文學參考資料小叢書, with a revised edition in 1979, and in 1986 the same publishing house launched a modern edition.