Maitreya's Ratnagotravibhaga, also known as the Uttaratantra, is the main Indian treatise on buddha nature, a concept that is heavily debated in Tibetan Buddhist philosophy. In A Direct Path to the Buddha Within, Klaus-Dieter Mathes looks at a pivotal Tibetan commentary on this text by Go Lotsawa Zhonu Pal, best known as the author of the Blue Annals. Go Lotsawa, whose teachers spanned the spectrum of Tibetan schools, developed a highly nuanced understanding of buddha nature, tying it in with mainstream Mahayana thought while avoiding contested aspects of the so-called empty-of-other (zhentong) approach. In addition to translating key portions of Go Lotsawa's commentary, Mathes provides an in-depth historical context, evaluating Go's position against those of other Kagyu, Nyingma, and Jonang masters and examining how Go Lotsawa's view affects his understanding of the buddha qualities, the concept of emptiness, and the practice of mahamudra.

Klaus-Dieter Mathes is a professor of Buddhist studies at the University of Hong Kong and was previously the head of the Department of South Asian, Tibetan and Buddhist Studies at the University of Vienna. His current research deals with exclusivism, inclusivism, and tolerance in Mahayana Buddhism. He obtained a Ph.D. from Marburg University and completed his habilitation at Hamburg University. His major publications include a study of the Yogacara text Dharmadharmatavibhaga (published in 1996 in the Indica et Tibetica series), A Direct Path to the Buddha Within: Gö Lotsawa's Mahamudra Interpretation of the Ratnagotravibhaga, and Maitripa: India's Yogi of Nondual Bliss.