The "Anūnatvāpūrṇatvanirdeśaparivarta" is a short Mahāyāna sūtra extant in its entirety only in Chinese translation. To judge from its use as a proof-text in the seminal philosophical treatise "Ratnagotravibhāga", which quotes roughly half of the sūtra, it is a fundamental scripture expressing ideas about the unitary nature of saṁsāra and nirvāṇa, and each individual’s innate capacity for awakening, called in this text and elsewhere ‘tathāgatagarbha,’ ‘embryo of the tathāgatas.’ Although the text has hitherto drawn the attention primarily of Japanese scholars, this is the first critical edition of the sūtra, aligning its Chinese text with the available Sanskrit, offering a richly annotated English translation, a detailed introduction which places the work in its historical and doctrinal context, and a number of appendices exploring key notions, providing a reading text shorn of annotation, and enumerating the prolific quotations of the work found in Chinese Buddhist literature. This volume is thus an important contribution to studies of developing Mahāyāna Buddhism, Buddhist doctrine and the textual history of scriptures.