The 2000 publication of a hitherto unknown Tibetan treatise on pramāṇaśāstra, entitled the Tshad ma de kho na nyid bsdus pa, raised considerable interest owing to its attribution to the great 14th century Rnying ma pa master Klong chen Rab ’byams pa (1308-1364). As Leonard van der Kuijp convincingly argued in an article published in the Journal of Indian Philosophy in 2003, however, this attribution of authorship was almost certainly incorrect. Notwithstanding this disappointment, the text is nevertheless of considerable interest, particularly in the light of the abundant new sources for the study of early Tibetan pramāṇa that have appeared in the Bka’ gdams gsung ’bum phyogs sgrig (Collected Writings of the Bka’ gdams pa). The presentation proposed here will examine anew the question of authorship and begin to place the work in its relation to newly published manuscript sources.