The Kunxuezhai zalu 困學齋雜錄 "Miscellaneous records of the Study of Difficulties in Learning" is a biji 筆記 "brush notes" style book written by the Yuan period 元 (1279-1368) scholar Xianyu Shu 鮮于樞 (1256-1301), courtesy name Xianyu Boji 鮮于伯機, style Xunxue shanmin 困學山民 or Jizhi laoren 寄直老人. He came from Dadu大都 (modern Beijing) and was manager of registration (dianbu 典簿) under the Chamberlain for Ceremonials (taichang 太常). Xianyu Shu was a famous calligrapher and poet and was highly admired by master Zhao Mengfu 趙孟頫. His collected writings are known as Kunxuezhai ji 困學齋集. The short book Kunxuezhai zalu is a draft-like collection of poetry critique and miscellaneous themes. The author was not recorded in the original edition, but only his style, so that Cao Rong 曹溶, compiler of the collectanea Xuehai leibian 學海類編, assumed that the author must have been Xianyu Shu. It is without doubt that the book was written by a person of a high eduction, although the book itself is a arranged in a rather loose way. Even the miscellaneous part includes interesting statments on poets in the Jin empire 金 (1115-1234) that are not to be found in Liu Qi's 劉祁 Guiqianzhi 歸潛志. The Kunxuezhai zalu is also to be found in the collectanea Siku quanshu 四庫全書, Jifu congshu 畿輔叢書 and Zhibuzuzhai congshu 知不足齋叢書.
Source: Li Xueqin 李學勤, Lü Wenyu 呂文鬰 (1996). Siku da cidian 四庫大辭典, Changchun: Jilin daxue chubanshe, vol. 2, p. 1963.