Nenggaizhai manlu 能改齋漫錄 "Loose records from the Studio of Possible Change" is a "brush-notes"-style book (biji 筆記) written during the Southern Song period 南宋 (1127-1279) by Wu Ceng 吳曾 (early 12th cent.), courtesy name Huchen 虎臣. He hailed from Chongren 崇仁 in the prefecture of Fuzhou 撫州 (modern Fuzhou, Jiangxi) and failed in the state examinations, but in 1141 presented his book to the throne, and was rewarded with the title of right gentleman for meritorious achievements (you digonglang 右迪功郎). From this position he rose to the position of right gentleman for attendance (you fengchenglang 右承奉郎), then recorder (zhubu 主簿) in the Court of the Imperial Clan (zongzhengsi 宗正寺), and was then made a career as aide of the Chamberlain for Ceremonials (taichang cheng 太常丞), ministerial director in the Ministry of Personnel (libu langzhong 吏部郎中), then that of Works (gongbu langzhong 工部郎中), and finally prefect of Yanzhou 嚴州.
His book of 18 juan length is divided into 13 chapters that each cover one aspect of literature, from scholarly treatises and textual critique to geography, historiography, poetry, prose literature, poems of the music-bureau style (yuefu 樂府) and bizarre stories. For most of these literary field, Wu Ceng has worked in a very scholarly way, with many quotations from ancient writings, to support his arguments. Because Wu Ceng was an adherent of the court faction of Qin Hui 秦檜 (1091-1155), he was criticized by many historians, like Liu Changshi 劉昌詩 (fl. 1216; author of Lupu biji 蘆浦筆記) or Zhao Yanwei 趙彥衛 (jinshi degree 1161; author of Yunlu manchao 雲麓漫鈔). On the other hand, Wu Ceng mentions many aspects of Qin Hui's administration that are not to be found in other sources, like the powerful counsellor's opinion of literature. Scholars of later decades again estimated the high value of his book and often quoted it. The Nenggaizhai manlu was as useful as the more famous Rongzhai suibi 容齋隨筆 by Hong Mai 洪邁 (1123－1202).
It is now known when the book was first printed. Zhou Hui 周輝 (b. 1127), author of Qingbo zazhi 清波雜志, has observed that Wu Ceng mentions the critique of a play by the Prince of Jing 荊 and some matters about problems in the imperial clan, and that the earliest prints might therefore have been proscribed by imperial order. Sheng Ruxin's 盛如梓 (early 14th cent.) book Shuzhai congtan 恕齋叢談 says that there was a certain Zheng Xianwen 鄭顯文, who sent his son Zheng Zhihan 鄭之翰 to the Censorate (yushitai 御史臺) to denounce Wu Ceng, so that, in the end, Wu Ceng and Zheng Xianwen were dismissed, yet some officials pledged for his innocence. From then on his book was given free for print. Regardless the question which of these texts tells the truth, it was a fact that Wu Ceng's book ceased to be in print at least from the Yuan period 元 (1279-1368) on.
During the Ming period 明 (1368-1644), several manuscripts of the Nenggaizhai manlu were discovered, for instance, by the collector Jiao Hong 焦竑 (1540-1620), and brought into circulation. These editions differ in the arrangement of juan, some are only 15-juan long, others 17. The compilers of the imperial series Siku quanshu 四庫全書 arranged it into 18 juan. The Nenggaizhai manlu is also included in the series Mohai jinhu 墨海金壺, Shoushange congshu 守山閣叢書, Biji xiaoshuo daguan 筆記小說大觀 (with a length of 18 juan), Cihua congbian 詞話叢編 (2 juan), Shuofu 說郛 (Wanwei Shantang 宛委山堂 edition, 1 juan), Wuyingdian juzhenban shu 武英殿聚珍版 and Congshu jicheng chubian 叢書集成初編. In the last edition, an appendix of fragments (Shiyi 拾遺) collected by Sun Xinghua 孫星華 is added. Modern editions were published in 1960 by the Zhonghua Shuju Press 中華書局, 1980 by the Shanghai Guji Press 上海古籍出版社, and 1987 by the Zhongguo Shangye Press 中國商業出版社 (with annotations by Wang Renxiang 王仁湘).