Introduction: What is an Upaniṣad? / Composition, authorship, and transmission of the Upaniṣad. The date of the Upaniṣads / The authorship of the Upaniṣads / The redaction and transmission of the Upaniṣads / The historical, cultural, and religious background of the Upaniṣad. Ancient India : geographical, historical, and cultural background / The older Vedas and the Upaniṣads / The religious and ritual background / The Upaniṣads and early Buddhism / The social background : caste and gender in the Upaniṣads / Religion and philosophy in the Upaniṣad. Prominent characters in the Upaniṣads / Ātman and Brahman in the Upaniṣads / Karma and rebirth in the Upaniṣads / Knowledge and liberation in the Upaniṣads / The upaniṣadic episteme / Mantras and sacred language / The Upaniṣads and the emergence of theism / The Upaniṣads and yoga / The Upaniṣads and the Mahābhārata / The Upaniṣads and the Bhagavadgītā / The Upaniṣads and later Hinduism / Dara Shikoh and the first translation of the Upaniṣads / Schopenhauer and the Upaniṣads / The classical Upaniṣad. The Bṛhadāraṇyaka Upaniṣad / The Chāndogya Upaniṣad / The Aitareya Upaniṣad / The The Kauṣītaki Upaniṣad / The Taittirīya Upaniṣad / The Īśā Upaniṣad / The Praśna Upaniṣad / The Muṇḍaka Upaniṣad / The Kaṭha Upaniṣad / The Śvetāśvatara Upaniṣad / The Kena Upaniṣad / The Maitrī Upaniṣad / The Māṇḍūkya Upaniṣad / The Mahānārāyaṇa Upaniṣad / The later Upaniṣad. The Vaiṣṇava Upaniṣads / The Śaiva Upaniṣads / The Devī Upaniṣads / The Saṃnyāsa Upaniṣads / The yoga Upaniṣads / Conclusion