SOURCE: Oldenberg, Hermann. Introduction to The Doctrine of the Upanisads and the Early Buddhism, translated by Shridhar B. Shrotri, pp. 1-21. Delhi, India: Motilal Banarsidass Publishers Pvt. Ltd., 1991.
In the following essay, Oldenberg provides background on Indian thought, including discussions of the Brahmana caste, sacrifice, and the otherworld.