The Upanishads are early philosophical texts of the Hindu religion. Originally written during 5th century BC and first translated into English in the early 19th century, they offer a doctrine on Hindu thought and culture and are perhaps the most important literature from ancient India. The Upanishads expound on principles like samsara, brahman, atman, karma, dharma and moksha and form the core of Indian philosophy. This version is an English translation by Swami Paramananda as part of his mission to spread the eastern teachings of Hinduism to the Western world. Paramananda was a mystic, a poet and one of the early Indian teachers who went to the United States to spread the Vedanta philosophy and religion. Using his experience as a religious scholar, Paramananda carefully translated the wisdom for Western readers.