Xu Le shu 徐樂書 "Book of Xu Le", also called Xu Le 徐樂, was a political treatise written by the Han-period 漢 (206 BCE-220 CE) official Xu Le 徐樂. He hailed from Wuzhong 無終 in the commandery of Yanjun 燕郡 (modern Beijing) and once submitted his book to the throne. For his helpful suggestions he was granted the title of gentleman of the interior (langzhong 郎中).
The imperial bibliography Yiwen zhi 藝文志 in the official dynastic history Hanshu 漢書 lists his book among the coalition advisors (zonghengjia 縱橫家). Xu Le was therefore also compared with the great coalition advisors Zhang Yi 張儀 (d. 310 BCE) and Su Qin 蘇秦 (late 4th cent. BCE) from the Warring States period 戰國 (5th cent.-221 BCE).
The book was lost at an early point of time, but the Qing-period 清 (1644-1911) scholar Ma Guohan 馬國翰 (1794-1857) collected surviving fragments of it. These are to be found in Ma's series Yuhan shanfang jiyi shu 玉函山房輯佚書.