Yamāri, an eminent eleventh-century Buddhist scholar (ca. 1000–1060), is renowned as the author of the Pramāṇavārttikālaṅkāranibandha, the second and last commentary on Prajñākaragupta’s Pramāṇavārttikālaṅkāra. This work has long been considered lost in its original Sanskrit. Only recently has it become known that a Sanskrit manuscript of this work is preserved in Lhasa, with a photocopy kept at the China Tibetology Research Center (CTRC) in Beijing. The manuscript covers the commentary on the Pramāṇasiddhi chapter of the Pramāṇavārttikālaṅkāra, which we propose to edit both diplomatically and critically. The present volume provides the first result of this endeavor. It contains a diplomatic edition, accompanied by critical notes, of ff. 3–107 out of the original 207 folios. These folios include Yamāri’s extensive introduction and a detailed commentary on the first 50 verses of the Pramāṇasiddhi chapter in Dharmakīrti’s Pramāṇavārttika and the Pramāṇavārttikālaṅkāra. Yamāri is a major representative of the Buddhist epistemology school, which applies Buddhist logic to religious issues such as the reliability of the Buddha, the existence of God, karma and rebirth, and the four noble truths, particularly the path to liberation.