Creator's Description: The extraordinary Dunhuang manuscript IOL Tib J 321 is a Rnying ma tantra commentary in eighty-five folios, the Thabs kyi zhags pa padma 'phreng gi don bsdus pa'i 'grel pa, with its important root tantra embedded as lemmata. Marginal notes associate the work with Padmasambhava. Although cited by Rong zom pa and Klong chen pa, later Rnying ma pas lost touch with the commentary, available to them only in truncated form within Bstan 'gyur editions. The Dunhuang manuscript now enables reconstitution of the entire commentary. More complex is the root text's transmission. Extant in all Ancient Tantra Collection of the Rnying ma pa (Rnying ma'i rgyud 'bum; NGB) and Bka' 'gyur Rnying rgyud sections, the versions can differ substantially, raising fundamental questions of textual boundedness. The differences derive from a thousand years of imprecise differentiation between root and commentary, which persisted unresolved from Dunhuang times until now. Rnying ma responses to uncertain scriptural boundaries entailed a distributive approach to knowledge, starkly contrasting many modern textual presuppositions.