Upanishad: The Basis for Hindu Philosophy

The Upanishads (teaching) form a series of discussions between teacher and pupil. They are philosophical and religious texts of Hinduism which put forth the essential tenets which form the foundation for the religion, making them perhaps the most important ancient Indian literature. There are around two hundred Upanishads, and they were translated into English in the 19th century.
The Upanishads deal with the individual’s place in the universe, the meaning of life, and other central doctrines. They represent humanity's desire for truth and understanding in plain, unvarnished prose or lucid rhyme by developing the concept of Brahman, the Supreme Soul (God) and the Atman (the individual’s higher self).
The Upanishads recognize the atman, a part of the divine Brahman that each individual carries. The goal of life was to be completely in touch with that higher self and, after death, be completely in unity with Brahman.
Each individual has a specific dharma (duty) for which they existed, and it must be performed with the correct karma (action). Evil is caused by failure to perform that dharma through the right karma.