Guo Shi is an author about whom public information is very limited: his dates of birth and death, native place, and official career remain unknown. The only work currently confirmed to be his is the single title The Outer Biography of Gao Lishi. This work belongs to the biographical writings of the Tang dynasty and centers on the life of the eunuch Gao Lishi, while also touching on court affairs and palace anecdotes from the Kaiyuan and Tianbao eras, preserving many details that can be consulted alongside the official histories. Its narrative is concise, following the subject's deeds as a thread and interspersing anecdotes in the manner of miscellaneous notes and informal biographies; it both fills gaps in historical biography and reflects contemporary observations of powerful eunuchs and the shifts between prosperity and decline. Because the author's life is difficult to examine in detail, scholarly discussion of the work's value tends to proceed from the text itself and its transmission. The book is often considered within the fields of ancient biography and Tang historical notebooks. In this catalog it is classified under Eastern philosophy, and readers may understand it in connection with the political and eunuch-system background of the Tang dynasty.
