Though Christians have been in India since late ancient times, we have no surviving witnesses to a pre-modern Christian siddhāntin tradition, one that might have taken its place in the hubbub of debate among late ancient and medieval Naiyāyikas, Vaiśeṣikas, Pūrva Mīmāṃsakas, Vedāntins, Buddhists, Sāṃkhyas, Jainas, Cārvākas, and so on. What would Christian theology look like were it forged in the crucible of these late ancient and medieval interreligious debates, responding to these Indian questions and elaborating answers within that spectrum of intellectual possibilities? This dissertation is a work of Christian comparative theology that addresses itself to that broader question, but by way of a focused engagement with the Indian Buddhist school Yogācāra. It takes up Indian Yogācārin accounts of nondual cognition (=buddhahood) from about the second to the eleventh centuries CE, and develops a critical Christian theological reception of those accounts, one articulated in Yogācārins' own technical terminology. The result is a critical philosophical basis for wider Christian theological receptions of these Buddhist accounts of nondual cognition, from Yogācāra, to Indo-Tibetan Mahāmudrā and Dzogchen, to the East Asian Buddhist traditions likewise indebted to Yogācārin teachings.After two introductory chapters, chapter 3 articulates a basic Yogācārin ontology of delusion and awakening in the terms of mind only idealism and the three natures, drawing from early and "classical" Yogācāra texts. Chapter 4 turns to Dignāga's and Dharmakīrti's account of nondual "reflexive awareness" (svasaṃvitti, svasaṃvedana) as the purely perceptual core of all cognitions as such. In Dharmakīrti's elaboration, this amounts to the claim that the ultimately real nature of all cognitions qua cognitive is buddha-awareness: a nondual luminosity always already intrinsically pure of the stain of duality. Chapter 5 takes up the Pratyabhijñā Śaiva authors Utpaladeva and Abhinavagupta, tracing their critical theist reception of Dharmakīrtian accounts of nondual reflexive awareness. These Indian theists' reception of Buddhist accounts of nonduality is instructive for Christians; it identifies, with a high level of technical specificity, the Dharmakīrtian positions that prohibit absolute theism, as well as the available theist alternative. Chapter 6 uses all the foregoing to develop a Christian reception of Yogācārin accounts of nondual cognition. It takes up Bernard Lonergan as its primary interlocutor, who also held that rational consciousness is "primarily" nondual, and that this primary nonduality is what makes the human spirit a created image of the "uncreated light." The preface and epilogue point to how this Christian theological reception of Yogācārin nonduality can underwrite a deeper reception of Indo-Tibetan Mahāmudrā for Christian contemplation, anthropology, and accounts of God.