In this book, the author provides philological and historical analysis of a Buddhist apocryphon from Early Medieval China, the Jingdu sanmei jing (Sūtra of Samādhi of Pure Deliverance). Excluded from the Buddhist Canon, this fifth-century apocryphal scripture is often cited in commentaries on canonical texts, doctrinal treatises and encyclopedic works. It is also known thanks to manuscript copies discovered in Dunhuang and to a copy found in the library of the Nanatsu-dera monastery in Japan. The author first presents its contents and then provides an analysis of the historical context in which it was written before exploring the important notions that it exposes about the “Thirty Hells”, the various deities responsible for evaluating human behavior, specific “retreats” (zhai) and religious practices promoted in its doctrinal system. An annotated translation of the first jian of the sūtra is given in the appendix. This work is not limited to the study of the text, but also addresses the role of apocrypha in the constitution of the Buddhist Canon. In addition, it analyzes the language of Chinese Buddhist texts and examines the interaction between Indian and Chinese concepts in Medieval Buddhism.