"The Ārya-saṃdhi-nirmocana-sūtra (Sanskrit) or Noble sūtra of the Explanation of the Profound Secrets is a Mahāyāna Buddhist text and the most important sutra of the Yogācāra school. It contains explanations of key Yogācāra concepts such as the basal-consciousness (ālaya-vijñāna), the doctrine of appearance-only (vijñapti-mātra) and the "three own natures" (trisvabhāva). Étienne Lamotte considered this sutra "the link between the Prajñaparamita literature and the Yogācāra Vijñanavada school".

This sūtra was translated from Sanskrit into Chinese four times, the most complete and reliable of which is typically considered to be that of Xuanzang. It also was translated into Tibetan. The original Sanskrit text has not survived to the present day."

"Like many early Mahāyāna sūtras, precise dating for the Saṃdhinirmocana Sūtra is difficult to achieve. Étienne Lamotte believed that the text was assembled from earlier, independent fragments. Other scholars believe that the apparently fragmentary nature of the early versions of the scripture may represent piecemeal attempts at translation, rather than a composite origin for the text itself. The earliest forms of the text may date from as early as the 1st or 2nd Century CE. The final form of the text was probably assembled no earlier than the 3rd Century CE, and by the 4th Century significant commentaries on the text began to be composed by Buddhist scholars, most notably Asaṅga."

             (from Wikipedia)

English translation:

     Unraveling the Intent (Saṃdhinirmocana)

Chinese translation:

     解深密經