This book offers a critical edition, translation and study of 62 Sanskrit verses from the Tattvasaṅgraha (an 8th-century Buddhist philosophical treatise by Śāntarakṣita) and their commentary by Kamalaśīla. The passage expounds and criticizes the definition of the Self (ātman) upheld by the greatest champion of Brahmanical orthodoxy, the Mīmāṃsaka philosopher Kumārila Bhaṭṭa (6th–7th century?). According to Kumārila, there is within each human being an enduring conscious substance the permanence of which ensures personal identity and justifies the Vedic injunction to sacrifice so as to enjoy later the results of the ritual. This entity is what we recognize when we say and think “I”: in the I-cognition we apprehend ourselves as the same consciousness that perceived in the past and is still aware now. Śāntarakṣita and Kamalaśīla, for their part, set out to defend the Buddhist doctrine that there is no Self (nairātmya) – according to which existential pain has as its root the erroneous belief in a permanent subject – by showing in particular that the self-recognition invoked by Kumārila is a mere mental construct. The text is an important document for the history of Indian philosophy, not only because it contains many quotations from the Bṛhaṭṭīkā (a lost work by Kumārila) and is probably the earliest preserved Buddhist critique of Kumārila’s definition of the Self, but also because it constitutes a splendid example of the way in which religious competition has stimulated and enriched philosophical debates in Medieval India. The book includes a study of the arguments put forward by Kumārila, Śāntarakṣita and Kamalaśīla (Chapters 1 and 2), an assessment of the originality and influence of Śāntarakṣita’s critique (Chapters 3 and 4), a tentative interpretation of the nature of the philosophical antagonism between Buddhist and Brahmanical milieux (Chapter 5), a critical edition and a translation of the text (Chapters 6 and 7). Table of contents available at https://paris3.academia.edu/IsabelleRati%C3%A9