There are two books with the title Guyue jingzhuan 古樂經傳 "Classic and commentaries to ancient music", one written during the Ming period 明 (1368-1644) by Zhan Ruoshui 湛若水 (1466-1560), and the other during the early Qing period 清 (1644-1911) by Li Guangdi 李光地.
Li Guangdi 李光地 (1642-1718), courtesy name Jinqing 晉卿, style Hou'an 厚庵, hailed from Anxi 安溪, Fujian, and obtained his jinshi degree during the Kangxi reign-period 康熙 (1662-1722). He rose to the eminent offices of governor (xunfu 巡撫) of Zhili 直隸 and was then made Grand Academician (daxueshi 大學士) in the Hall of Literary Profundity 文淵閣. Except the Guyue jingzhuan he wrote several commentaries on Confucian Classics like Zhouyi tonglun 周易通論, Shangshu jieyi 尚書解義 and Xiaojing quanzhu 孝經全注, and other ancient texts like Lisao jingzhu 離騷經注, Er Cheng yishu 二程遺書 – a compilation of the writings of the Neo-Confucian philosophers Cheng Hao 程顥 (1032-1085) and Cheng Yi 程頤 (1033-1107) – and the collection Guwen jingzao 古文精藻).
His 5-juan long Guyue jingzhuan is a commentary to the music of the Zhou period 周 (11th cent.-221 BCE) as presented in the Classic Zhouli 周禮. The twenty offices under the Musician-in-chief (dasi yue 大司樂) are regarded as the "classic", and the chapter Yueji 樂記 from the Classic Liji 禮記 as the "commentary". Li Guangdi adds two further commentaries called "Appended Classic of Music" (Fu yuejing 附樂經) and "Appended Records of Music" (Fu yueji 附樂記).
His grandson Li Qingzhi 李清植 (1690-1744), courtesy name Lihou 立侯, style Muting 穆亭, supplemented two chapters found in Guangdi's literary remains, namely Yuejiao 樂教 "Education in music" and Yueyong 樂用 "The use of music".
What makes Li Guangdi's book very outstanding is his theory that the measures of the pitchpipes are instruments to join the Heavenly spirits in a fourfold way. The book was therefore included in the imperial series Siku quanshu 四庫全書, and is also to be found in Li's collected writings Li Wenzhengong quanji 李文貞公全集 and the collection Rongcun quanshu 榕村全書.
Zhan Ruoshui's 3-juan long Guyue jingzhuan consists of several separate texts that were partially written by Zhan Ruishui himself, and partially by his disciples. The first chapter, Jingzhuan 樂經, is defined as the "original" classic on music, but was written by Zhuo himself. The 10-parts long Guyue zhengzhuan 古樂正傳 "Correct commentary to ancient music" is a product of Lü Huai 呂懷 (1492-1573). The chapter Guyue benzhuan 古樂本傳 "Basic commentary to ancient music" is actually the original text of the chapter Yueji 樂記 in the Confucian Classic Liji.
The chapter Biezhuan 別傳 "Alternative commentary" is a collection of statements on music in the Classic Zhouli. In the chapters Zazhuan 雜傳 "Miscellaneous comments" and Lüzhuan 律傳 "Comments on the pitchpipes" Zhan Ruoshuo assembled theoretical statements on music by later authors, beginning with the time of Mengzi 孟子.
The chapters of the book focus on the right measures of the pitchpipes that reflect a certain order in society and the universe. The problem in his treatment of the ancient chapter Yueji as a classic and all younger texts as "commentaries" is that it is not known anything about the measures for musical tuning during oldest times, and Zhan Ruoshui therefore looses himself in a lot of speculations.
Zhan Ruoshui's Guyue jingzhuan is described in the catalogue Siku quanshu zongmu tiyao 四庫全書總目提要, but the text is not included in the Siku quanshu itself.