1. Upa- (near), ni- (down), sad (to sit): sitting near the teacher
Transmission of knowledge by way of a guru or teacher.
Upanishad
Upa- (near), ni- (down), sad (to sit): sitting near the teacher

2. Six Primary Concepts of the Upanishads
The 10 principal Upanishads are Isa, Kena, Katha, Prasna, Mundaka, Mandukya, Chandogya, Brhadaranyaka, Aitareya, and Taittiriya.
Brhadaranyaka, Chandogya, Taittiraya, Aitareya, and Kena are pre 6th century BCE.
Katha and Mundaka are 6th century BCE.
Praana and Mandukya are 5th to early 4th century BCE.

3. I.
BRAHMAN

4. The Upanishads emphasize the impermanence of the empirical world, physical reality as we experience it through our senses.
Maya
Maya = “that which is not [real or permanent],” though it appears to be.

5. Beyond Maya, there is an unchanging reality called
Brahman
(lit. “to expand”)

6. Four Claims about Brahman
Brahman is the fundamental principle of the universe. (Kena Upanishad IV and V)
Brahman is the reality in all, and all things are in Brahman. (Svetasvatara Upanishad, IV. 2–4)
Brahman is the state of non-duality. (Brhadaranyaka Upanishad, IV.v.14–15)
Brahman is Ineffable. (Kena Upanishad, I.5-9)
Supporting Passages from the Upanishads
“This is the truth of Brahman in relation to nature: whether in the flash of the lightning, or in the wink of the eyes, the power that is shown is the power of Brahman.” Kena, IV.4
“This is the truth of Brahman in relation to men: in the motions of the mind, the power that is shown is the power of Brahman.” Kena, V.
“Self-luminous is Brahman, ever present in the hearts of all. He is the refuge of all, he is the supreme goal. In him exists all that moves and breathes. In him exists all that is.” Mundaka, II.i.1-2.
“Thou art the fire, the sun, the air, the moon, the starry firmament, Thou art Brahman Supreme: Thou art the waters – Thou, the creator of all!
“Filled with Brahman are the things we see; Filled with Brahman are the things we see not;
From out of Brahman floweth all that is; From Brahman all – yet is he still the same.” Svetasvatara, IV.2–4
“As long as there is duality, one sees the other, one hears the other, one smells the other, one speaks to the other, one thinks of the other, one knows the other; but when for the illumined soul the all is dissolved in the Self, who is there to be seen by whom, who is there to be smelt by whom, who is there to be heard by whom, who is there to be spoken by whom, who is there to be thought by whom, who is there to be known by whom.” Brhadaranyaka, IV.v.14–15
“By whom shall the knower be known? The Self is described as not this, not that. It is incomprehensible, for it cannot be comprehended; undecaying, for it never decays; unattached, for it never attaches itself; unbound, for it is never bound.” Brhadaranyaka, IV.v.14–15
“That which cannot be expressed in words but by which the tongue speaks – know to be Brahman. Brahman is not the being who is worshipped of men.
“That which is not comprehended by the mind but by which the mind comprehends – know that to be Brahman. Brahman is not the being worshipped of men
“That which is not seen by the eye but by which the eye sees – know that to be Brahman. Brahman is not the being worshipped of men.
“That which is not heard by the ear but by which the ear hears - know that to be Brahman. Brahman is not the being who is worshipped of men.
“That which is not drawn by the breath but by which the breath is drawn - know that to be Brahman. Brahman is not the being worshipped of men. ~ Kena, I.5-9

7. Brahman as the Impersonal Absolute
The central claims of the Upanishads about Brahman suggest that Brahman is not a personal being, not a being with attributes that characterize “persons” (e.g., self-awareness, perspectival experience, deliberative rationality, and being the subject of intentional states).
On this view, Brahman is formless or attributeless (nirguna) and not a personal God.

8. If Brahman is without form, then “gods” represent different provisional manifestations of Brahman.
The Trimurti was systematized in the Puranas composed during the Gupta Period ( CE), after the ascendency of the Brahma, Vishnu, and Shiva, “God forms” were widespread in Indian culture.
Brahma
Vishnu
Shiva
The Trimurti (three forms) represent Brahman manifested in the processes of creation, preservation, and dissolution and recreation of the cosmos.

9. Brahman as Personal God
The Upanishads also refer to Brahman under various attributes (saguna Brahman), including those indicative of personhood: knowledge, will, and moral goodness (Svetasvatara Upanishad, VI.1-23).
Some passages in Mundaka Upanishad subordinate imperishable Brahman to the supreme “Purusha” (person).
Other later Upanishads emphasize personal theism (e.g. Katha, Isa, and Svetasvatara).
See R.C. Zaehner, Hindu and Muslim Mysticism, chapter 2.
“Heavenly, formless is the Person [Purusha], He compromises without and within, unborn is he; without breath, without mind, effulgent, higher than the high imperishable [i.e., Brahman].” Mundaka, 2.I.2 Cf. 3.I. 13.

10. Brahman as Creator?
The Upanishads speak of Brahman as creator. However, even where Brahman is conceived of in personal terms, “creation” refers to a necessary emanation of the universe from the being of Brahman, like the flowing of a web from a spider. The Upanishads affirm eternal, cyclical processes of the origination of order, its evolution, and eventual dissolution.
"Bliss [ananda] is Brahman, for from bliss all beings are born; by bliss, when born, they live; and into bliss they enter at their death." ~ Taittiriyaka Upanishad, III.6

11. (Taittiriyaka Upanishad, III.6)
"Bliss [ananda] is Brahman, for from bliss all beings are born; by bliss, when born, they live; and into bliss they enter at their death."
(Taittiriyaka Upanishad, III.6)

12. II. ATMAN

13. The Upanishads teach the existence of a true Self called Atman.
The True Self (Atman)
The Upanishads teach the existence of a true Self called Atman.
Atman is distinguished from the individual personality or ego formed through attachments to sense objects.
The individual self is subject to the laws of karma and rebirth. This can only be transcended through knowledge of the true nature of the self and reality. See subsequent power points on avidya, karama, samsara, and moksha.
The true Self of each person is not identical with the body or a person’s mind as conditioned by sense experience.

14. Atman is Pure Consciousness
Atman is simply consciousness or awareness without objects. Hence atman is called “pure awareness” or “non-differentiated consciousness.”
Atman is distinct from the mind, for the mind is consciousness conditioned by objects and hence duality (subject-object relation).
The “separate ego” or “false self” is an identification of the “I” with sensing, perceiving, and thinking, or the objects given through these changing mental processes. “I am this” “I am that.”

15. Atman is Pure Consciousness
Atman is the enduring and ever-present “I” behind changing “states” of consciousness, the witnessing background of all experience.
Unlike the body and the mind, Atman is eternal, unborn, and unlimited.
Many Upanishads deny that Atman is an individual consciousness. It is non-dual consciousness or universal consciousness, from which it follows that the Atman of each person is the same reality.

16. “The wise one is not born, nor dies.
This one has not come from anywhere, has not become anyone.
Unborn, constant, eternal, primeval, this one
Is not slain when the body is slain
He who is the bodiless among bodies,
Stable among the unstable.
The great, all pervading Self –
On recognizing Him, the wise man sorrows not.”
Kena Upanishad II.18,22

17. “That Self (Atman) is not this, it is not that (neti, neti)
“That Self (Atman) is not this, it is not that (neti, neti). It is unseizable, for it cannot be seized; indestructible, for it cannot be destroyed; unattached, for it does not attach itself; is unbound, does not tremble, is not injured.”
Brhadaranyaka Upanishad, iv.v.15

18. Relation between Brahman and Atman

19. “Thou [Atman] art That [Brahman]”
Tat Tvam Asi
“Thou [Atman] art That [Brahman]”
(Chandogya Upanishad, VI)
A famous and controversial passage from the Upanishads.
Atman and Brahman are identical?
Atman and Brahman are united in some way without being entirely identical?

20. III. AVIDYA

21. The human perspective is characterized by ignorance (avidya) of the true nature of reality and the self.

22. Human persons identify themselves with their body or with their individual states of consciousness formed through contact with and attachment to sense objects. This is the false ego or false self.

23. The false ego is the source of human suffering or unhappiness because the false ego is a product of attachments to what is non-enduring.

24. IV. SAMSARA and KARMA

25. The Upanishads teach that all life forms move through repeated cycles of birth, death, and rebirth, until final liberation from this cycle.

26. The cycle of death and rebirth is called Samsara.
Its fuel or energy is called
Karma.
The termination of the cycle is called
Moksha.

27. “Where one’s mind is attached – the inner self
Goes thereto with action, being attached to it alone.
Obtaining the end of his action,
Whatever he does in this world,
He comes again from that world
To this world of action.
- So the man who desires.”
Brhadaranyaka Upanishad, iv.iv.6

28. Rebirth is fueled and directed by karma
(sanskrit root kri, meaning “action”).
More technically, karma designates a law of cosmic justice according to which every action has an effect that is proportioned to the moral quality of the action.
Broadly stated, karma is a law of cause and effect according to which actions in one lifetime influence actions in the next life.

29. Attachment to material forms of existence (modes of false ego) is the basic karmic energy that fuels samsara.
The form of one’s karma is shaped by the specific nature of one’s attachments.

30. Rebirth is not restricted to rebirth as a human being, but it extends to the animal world and other realms of existence.
The form of one’s karma (good or bad) determines the realm of existence into which one is reborn.

31. Rebirth is not desirable.
It implies that a person is still trapped in ignorance about the nature of reality through various attachments to sense objects.
Suffering, associated with material existence, has not yet been transcended.

32. V. MOKSHA

33. Moksha is the state of release from samsara.
Attachments => False Ego => Karma => Samsara
What is required is a dismantling or dissolution of the false ego. Therefore, we must let go of our attachments to sense objects or material forms of existence.

34. Destruction of the False Ego
Spiritual discipline dismantles the false ego: Spiritual Practice Consists in Observing Moral Laws (aimed at renunciation of material attachments) and Meditation
Moral laws included the study of scripture, honesty, self-denial, practice of austerity, self-control, and cheerful fulfillment of everyday duties. The fundamental aim of the moral laws is self-abnegation and renunciation of all selfish desires. See Prabhavanada, Spiritual Heritage of India, pp

35. Destruction of the False Ego
Since the false ego is generated by attachments to sense objects, it is dissolved by non-attachment to sense objects.
Attachment to sense objects creates a disturbance in consciousness. Meditation (dhyana) stills or quiets consciousness, allowing realization of Atman.
Non-attachment and meditation operate in tandem. To concentrate the mind on one thing releases the attention given to other things. Hence, meditation assists non-attachment to sense objects.

36. Meditation
Having heard and reflected on the word of Brahman in the scriptures, one must practice concentration on the truth of Brahman and the Self, repeating mantras such as OM (which signifies the cosmic power of Brahman) or
Aham Brahmasmi
(I am Brahman).
Specific meditation techniques were passed on through one’s personal guru so there is no specific account of methods in the Upanishads.

37. Neti, Neti
The Upanishads also teach that atman is realized by (i) identifying the temporary nature of the mind-body, which we mistake for the Self and (ii) thereby realizing that the “I” is distinct from the mind-body.
This is called “neti, neti” meaning “not this, not that.”
Through meditation, the subject realizes “I am not my thoughts; I am aware of my thoughts,” “I am not my feelings; I am aware of my feelings,” “I am not this sensation; I am aware of this sensation.” Thus, I am awareness, the witnessing background of all experience.

38. The Ultimate State (Moksha)
Spiritual practice leads to Moksha (liberation)
Moksha is freedom from samsara and thus freedom from suffering.
Moksha is absolute consciousness: “Brahman realization” and “Self realization” since the true nature of reality (Brahman) and the true self (Atman) is perceived.
Desire for transient things limits freedom, so only that which eliminates desire can be free.

39. Realization of Brahman and the Self Sat-Chit-Ananda Being (Sat)
Consciousness (Chit)
Bliss (Ananda)
“Happiness is nothing less than the Infinite, for there is no happiness in what is small.” Chandogya Upanishads, VII, xxiii.
Satchitananda is also the name of Brahman.
So moksa is union with Brahman.

40. “As rivers flow into the sea and in so doing lose name and form, even so the wise man, freed from name and form, attains the Supreme Being, the Self-luminous, the Infinite.” Chandogya, VI.i.5

41. Six Primary Concepts in the Upanishads
Atman
Brahman
Avidya
Karma
Samsara
Moksha

42. References
Steven Rosen, Essential Hinduism (Westport, CT: Praeger, 2006).
R.C. Zaehner, Hindu and Muslim Mysticism (New York: Schocken Books, 1969), Chapters 2-4.
R.C. Zaehner, Hinduism (New York: Oxford University Press, 1972).
Swami Prabhavanda, The Spiritual Heritage of India: A Clear Summary of Indian Philosophy and Religion (Hollywood, CA: Vedanta Press, 1979), Chapters 1-3.
Keith Ward, Concepts of God: Images of the Divine in Five Religious Traditions (Oneworld, 1998), Chapters 1-2.
Hans Torwesten, Vedanta: Heart of Hinduism (New York: Grove Press, 1991), Chapter 1.
Dominic Goodall (ed.), Hindu Scriptures (Berkeley, CA: University of California Press, 1996).