Krishnamacharya on Kuṇḍalinī explores a distinctive teaching of 'the father of modern yoga', T. Krishnamacharya. Whereas most yoga traditions teach that kuṇḍalinī is a serpentine energy that rises, Krishnamacharya defined it differently. To him, kuṇḍalinī is a serpentine blockage which prevents prāṇa (breath or life-force) from rising and which represents avidyā (spiritual ignorance). Simon Atkinson draws from over 20 years of study and practice under teachers following Krishnamacharya. He combines analysis of quotations from yoga workshops with a detailed study of traditional Sanskrit texts. He traces the textual origins of Krishnamacharya's position to two sects of Viṣṇu-worshiping temple priests, and shows how it is compatible with a stream of South Asian thought where snakes represent something to be overcome. Atkinson challenges claims that Krishnamacharya's position can be found in his religious tradition of Śrīvaiṣṇavism. He questions the tradition's reliance on textual sources, showing how the coherence of Krishnamacharya's position can only be maintained by employing elaborate arguments and rejecting texts that teach otherwise. Atkinson also explores how Krishnamacharya's teaching on kuṇḍalinī influences how yoga is practised. He argues that Krishnamacharya's position is best viewed as a model for experience that guides practice.