Simply keeping the mind clear and calm was, for many post-Tang Daoists, the path to eternal life and freedom. Through sheer serenity, practitioners believed they could attain immunity to hunger, eliminate sexual function, suspend breath and pulse, engage in astral travel, and command spirits and natural forces. In his meticulously researched study, Stephen Eskildsen examines how this perspective informed Daoist internal alchemists after the Tang dynasty (618–907), including prominent representatives of the Quanzhen tradition in the north and the Nanzong in the south. Drawing on a wide array of textual sources, he analyzes the teachings of figures like Qiu Chuji (1143–1227), Yin Zhiping (1169–1251), Zhang Boduan (ca. 984–1082), Bai Yuchan (1194–1229), Li Daochun (fl. 1288–1292), Yu Yan (ca. 1253–1314), and Wu Shouyang (1574–after 1641), among others. These adepts emphasized passive, straightforward methods that they believed gave rise to spontaneous psychic, sensory, and physiological phenomena—approaches they considered more effective than manipulating mind and body with overly complicated techniques. Eskildsen shows how Daoist internal alchemists, by advocating for the maintenance of serenity throughout a mundane life, articulated a unified vision of the Three Teachings—Daoism, Confucianism, and Buddhism—and frequently cited Confucian and Buddhist texts while reinterpreting and adapting their teachings. Particularly notable is their creative reinterpretation of Buddhist concepts such as "non-leakage" and the "Marks of the Great Man," and their integration of ideas pertaining to the "mind-made body" and the intermediate state. Incorporating such elements played a critical role in shaping their vision of the ultimate soteriological goal: the completion and emancipation of the Yang Spirit. In turn, this Daoist synthesis prompted some to propagate—or ostensibly revive—a Buddhist internal alchemy. Offering a compelling contribution to the understanding of Daoism after the Tang, Eskildsen sheds light on a strand of internal alchemy that pursued the sustained cultivation of mental clarity and equanimity above all else.