  Two chapters in the current Hanfeizi (chs. 21 and 22) are entitled “Explaining (the Sayings of) Laozi” (Jie Lao) and “Illustrating (the Sayings of) Laozi” (Yu Lao), which can be regarded as the earliest extant commentary to the classic (for a detailed study and translation, see Sarah A. Queen 2013). The “bibliographical” section of the Hanshu (History of the Former or Western Han Dynasty) lists four commentaries to the Laozi, but they have not survived. Nevertheless, Laozi learning began to flourish from the Han period. The commentaries by Heshanggong, Yan Zun, Wang Bi, and the Xiang’er commentary will be introduced in what follows. Some mention will also be made of later developments in the history of the Daodejing. The late Isabelle Robinet has contributed an important pioneering study of the early Laozi commentaries (1977; see also Robinet 1998).