The Illumination of the Thought (dbu ma dgongs pa rab gsal) is one of two major works by Tsong-khapa to comment directly upon and incorporate an Indian Madhyamika text. It is also the last of his five works on Madhyamika, written in 1418, the year before his death, when he was sixty-one years old. This text, among the last in a lifetime of writing that produced over two hundred separate titles occupying eighteen Tibetan volumes, can be located in other ways as well. On the one hand, it takes its place in a lineage of textual commentary considered to link the turn-of-the-millennium Nagarjuna and the seventh-century Candrakirti with the fourteenth-century Tsongkha-pa. Innumerable other voices, including a wide of range of Buddhist scriptures and the opponents whose views he debated, also surface in this text. The other locus, and the one to which this volume directly addresses itself, is the place of Tsong-kha-pa's work in the living oral philosophical traditions of Tibet. It is in this latter context that Tibetans encounter texts such as this, whether as monas- tic scholars listening to it from their teachers and debating its fine points with their peers, or more rarely as members of the lay public who gather on special occasions to hear discourses on it from renowned lamas.

Nagarjuna, the initial systemizer of Indian Madhyamika, formed the basis for virtually all subsequent Indo-Tibetan Madhyamika studies with his Treatise on the Middle Way (dbu ma'i bstan beos, mülamadhyamakasastra). Candrakirti, who studied and then became abbot at the famous Buddhist Monastic University of Nalanda in the post-Gupta period, marked a turning point in Indian Madhyamika. His Entrance to the Middle Way (dbu ma la jug pa, madhyamakavatara) expanded greatly on Nagarjuna's writing and paved the way for a new vision of Madhyamika known as Prasangika- Madhyamika. Candrakirti organized his discussion around the ten Bodhisattva grounds (sa, bhumi), and his interweaving of practical guidelines-such as detailed descriptions of the perfections of giving, ethics, and patience-as well as philosophical analysis, struck a deep chord in Tibet, where a whole class of literature outlining the stages of the path (lam rim) grew up on this model, with Tsong-kha-pa's own work one of its supreme exemplars.

Kensur Yeshey Tupden's oral scholarship on a major text of his tradition invites us to consider the place of orality in Tibetan scholarly traditions, and especially the relationship between oral genres and the philosophical categories and ritual expressions of Tibetan Buddhism. I see Tibetan oral genres as falling into two broad categories. The first is explanatory, such as the oral philosophy translated here, and its primary purpose is to amplify the meaning of a text. The second is more ritualistic, for it includes vocalizations in which sound rather than meaning is paramount, such as the recitation of mantra or other rhythmic chanting.

Tibetan oral performances vary considerably in how they balance explanatory and ritual power, some utilizing one genre almost to the exclusion of the other, some having both but emphasizing one or the other. In practice, therefore, these two genres are often intertwined.