The Upanisads, the basic philosophical texts of Hinduism, represent the height of Vedic philosophy. Many of the older Upanisads can be dated in the eighth and seventh centuries DC. The newly reissued The Principal Upanisads, S. Radhakrishnans, first published in 1953 and long out of print, contains in full the classical Upanisads, those commented on or mentioned by the eighth-century Indian philosopher Shankara. The Sanskrit text, transliterated into Roman script, is followed, verse-by-verse, with an English translation. The volume also included a commentary on the argument, notes on the vocabulary, and a very detailed introduction by Dr. Radhakrishnan.