The Upanishads speak in visions, dialogues and paradoxes, and by the close of the Vedic age their teachings could be read in more than one way. The Brahma Sutras exist to settle the reading. Across four chapters, each divided into four quarters, the work proceeds as a jurist proceeds: it takes up the disputed passages of the Upanishads topic by topic, states the doubt, considers the opposing view, and rules. The first chapter, on harmony, argues that the scattered texts converge on Brahman as the single source of the world; the famous second sutra defines Brahman as that from which the origin, subsistence and dissolution of this world proceed. The second chapter answers objections, engaging the rival systems of the day, Samkhya above all, whose unconscious primal matter the sutras reject as unable to account for an ordered world, along with atomism and Buddhist positions. The third chapter turns to the means of realisation, the meditations and knowledge by which the self approaches Brahman, and the fourth to the fruit, the path of the departing soul and the nature of liberation. The style is radically economical, often two or three words relying on context, which made the sutras a frame that could hold argument but never end it: precision of structure joined to openness of meaning, an invitation to commentary that Indian philosophy accepted for over a thousand years.