of the Ātman. The different Avatārs of Vishṇu are here regarded as human manifestations of the Ātman.
The oldest and most important of these Atharvan Upanishads, as representing the Vedānta doctrine most faithfully, are the Muṇḍaka, the Praçna, and to a less degree the Māṇḍūkya. The first two come nearest to the Upanishads of the older Vedas, and are much quoted by Bādarāyaṇa and Çankara, the great authorities of the later Vedānta philosophy. They are the only original and legitimate Upanishads of the Atharva. The Muṇḍaka derives its name from being the Upanishad of the tonsured (muṇḍa), an association of ascetics who shaved their heads, as the Buddhist monks did later. It is one of the most popular of the Upanishads, not owing to the originality of its contents, which are for the most part derived from older texts, but owing to the purity with which it reproduces the old Vedānta doctrine, and the beauty of the stanzas in which it is composed. It presupposes, above all, the Chhāndogya Upanishad, and in all probability the Bṛihadāraṇyaka, the Taittirīya, and the Kāṭhaka. Having several important passages in common with the Çvetāçvatara and the Bṛihannārāyaṇa of the Black Yajurveda, it probably belongs to the same epoch, coming between the two in order of time. It consists of three parts, which, speaking generally, deal respectively with the preparations for the knowledge of Brahma, the doctrine of Brahma, and the way to Brahma.
The Praçna Upanishad, written in prose and apparently belonging to the Pippalāda recension of the Atharva-veda, is so called because it treats, in the form of questions (praçna) addressed by six students of Brahma to the sage Pippalāda, six main points of the
