The Mulapariyāya Sutta, is considered one of the most important texts in the Pāli Canon. The Buddha taught it to clear away the mental obstructions preventing a correct grasp of his teaching and to open the way for insight to arise. It aims at eliminating the whole range of subjective misconceptions centered on the concept of an ego right down to their roots. It reveals the structure of man's ego-biased orientation towards the world, shows the way this mental stratification colors and distorts his understanding, and points out the work of inner re-orientation he must do to free himself from his egoistic bonds. The present work offers an English translation of the discourse together with its commentarial exegesis, essential for understanding the many difficult passages occurring in the primary text. The presentation gives the sutta first, then follows it with an exegetical section containing the commentary and selected passages from the subcommentary. The introduction provides a detailed guide to the meaning of the sutta and explores its implications for epistemology, ontology, and psychology. It discusses important topics dealt with in the discourse such as the structure of ego- consciousness. 2024 Pariyatti Press Edition