Dzogchen teaching discourse typically comprises presentations of the essence, nature, and compassion of the basis. Among these three concepts, the essence—original purity (tib. ka dag)—is the focus of the course’s second lesson. Malcolm characterizes this original purity on the basis of a detailed section (never before presented in English) on the ten pristine consciousnesses found in the Realms and Transformations of Sound Tantra (tib. sgra thal ’gyur gyi rgyud). Cataloging the varied interpretations of the term often translated as “clear light” (skt. prabhāsvara; tib. ‘od gsal), Malcolm establishes the concept of primordial buddhahood and discusses original purity as a mere negation—“that in which no ignorance has ever existed.” He explains how understanding this original purity necessitates a comprehensive explanation of ignorance and how it arises that is not present in any other category of Buddhist teachings.