Rigved, Yajurved, Samaved and Atharvaved are the four Vedas. Each of the four Vedas is divided into 2 kandas or sections- The ‘Karma kanda’ (work section) consisting of Samhita, Brahmana and Aranyaka and ‘Jnana kanda’ (knowledge section) consisting of Upanishads. These 2 sections are also termed as “Poorva mimansa” and “Uttara mimansa” respectively. Sage Veda Vyasa analyzed the Jnana kanda and realized that it was the quintessence of the Vedas. Once the materialistic rites in the Vedas are duly performed, a person should concentrate on the spiritual aspect i.e. the Upanishads. The word ‘Upanishad’ is derived from the Sanskrit root ‘upa+ni+sada’ meaning ‘to sit down near (someone)’. However, there are several other meanings of the word ‘Upanishad’. They are as follows-
· Secret knowledge obtained from a Preceptor
· Transcendental truth
· Truth about the Supreme Reality (i.e. Parabrahman)
· A thing that takes us close (to Parabrahman)
· A secret doctrine
· Something that enhances strength, firmness and detachment
The Upanishads come towards the end of the Vedas. Therefore, they are called as ‘Vedanta’. Another reason for calling them Vedanta is that Upanishads are the final word of the Vedas. They are the core essence of the Vedas. There is no other knowledge that is higher than that given in the Upanishads. The Upanishads are scriptures that display the most scientific spirit in connection with spiritual enquiry.
According to Almond Holmes, “The Upanishads are the highest and purest expression of the speculative thought in India.”
Moreover, Annie Besant says, “I regard the Upanishads as the highest product of human mind, the crystallized wisdom of divinely illumined men.”
The Era of Upanishads
Hardly anyone knows about the exact date when the Upanishads were written. According to modern academics, the early Upanishads were composed over two thousand five hundred years ago, before the time of the Buddha. The Buddha lived around 500 B.C.; many of the major Upanishads were composed earlier. The time period when the Upanishads were written was approximately between 5000 B.C.E to 600 B.C.E. Despite the uncertainty, one thing is clear. The Upanishads are part of a very long tradition of knowledge, which has been developing over many thousands of years. And this tradition is not just a dead remnant from the past. It is very much alive today. It is a living tradition that has been passed down in an unbroken line from teacher to disciple, through all the social and cultural upheavals that have taken place.
The Authors of Upanishads
We do not know the authors of the Upanishads as historical persons. We do not know where or when they lived, or who they were. The Vedas and the Upanishads are called ‘shruti’ which literally means that which is heard. It is traditionally believed that the Upanishads were the intuitions of certain sages. The divine and supreme knowledge of the Upanishads was received as a realization or as a revelation directly from God. These sages hence are called Seers.
The Number of Upanishads
The Muktikopanishad speaks of 108 Upanishads. Of these, 10 are in Rigved viz. Aitareya, Nirvana, Atmabodhaka, Nadabindu etc. Shukla Yajurved contains 19 Upanishads viz. Brihadaranyaka, Ishavasya, Advaita, Hamsa, Jabala etc. Krishna Yajurved contains 32 Upanishads viz. Katha, Brahma, Narayana, Rudrahridaya etc. Samaved contains 16 Upanishads viz. Chhaandogya, Kena, Aruneyi, Rudraksha, Darshana etc. Atharvaved contains 31 Upanishads viz. Prashna, Mundaka, Maandukya, Kaivalya, Parabrahma, Krishna etc. Of the 108 Upanishads, 10 are considered to be of prime importance because of Adishankaracharya’s commentary on them. These Upanishads are-
ईशकेनकठप्रश्नमुण्डमाण्डूक्यतैत्तिरी:
ऐतरेयं च छान्दोग्यं बृहदारण्यकं तथा
The Ten Upanishads
Isha, Kena, Katha, Prashna, Munda, Maandukya, Taittiri, Aitareya, Chaandogya and Brihadaranyaka are the ten widely studied Upanishads.
Isha Upanishad
Ishopanishad appears at the end of Shukla Yajurved Samhita. It is so called because it begins with the words “isha vaasyam” It contains 18 mantras. It begins by saying that God pervades the whole world and we should reach the state of realizing the ‘paramatma tattva’, by offering the fruits of all actions to Him alone.
ईशावास्यम् इदं सर्वं यत् किं च जगत्यां जगत्
तेन त्यक्तेन भुञ्जीथा मा गृधः कस्यस्विद धनम्
Kena Upanishad
Kenopanishad is so called because it begins with the word “kena” meaning ‘by whom’. It is also called as ‘Talavakaara Upanishad’ because it appears in the Talavakaara Brahmana of the Jaimini branch of Saama Veda. This Upanishad contains 4 parts of which first two are in poetry form while the next two are in prose form. This Upanishad describes how Ambika Herself, the Divine Mother, imparted divine wisdom to Indra, the king of the deities, who was unable to find the eternal Paramatma in his pride.
Katha Upanishad
The Kathopanishad or Kathakopanishad appears in the Kathaka branch of the Krishna Yajurved. It contains the dialogue between Yama, the God of death, and a brahmachari lad named Nachiketa dealing with the question of what happens to the soul after death. It proclaims the immortality of the soul and the mortality of the body e.g.
न जायते म्रियते वा विपश्चिन्
न अयं कुतश्चिन्न बभूव कश्चित्
अजो नित्यः शाश्वतोऽयं पुराणो
न हन्यते हन्यमाने शरीरे
Prashna Upanishad
Prashna Upanishad appears in the Atharvaved. Prashna means ‘question’. Prashnopanishad answers the following six questions- How did creation begin? Who are Devas? How does life get connected to the body? What is the truth about the states of awakening, sleep and dreaming? What is the benefit of worshipping Omkaara? What is the relationship between the Purusha and Jiva? Prashna Upanishad provides answers to these questions and hence the name.
Munda Upanishad
Munda or Mundaka Upanishad belongs to the Atharvaved. ‘Mundaka’ means a shaven head. Mundakopanishad is to be followed by persons like Sanyaasins, with mature minds and a disposition free from attachment. This Upanishad talks of ‘Akshara Brahman’ which means ‘that which is free from decay or dissolution’. ‘Akshara’ also means sound or syllable. To reach the aim of Akshara Brahman, the akshara or syllable ‘Om’ plays the chief role. This Upanishad says that the arrow of the Atman should be shot from the bow of Omkaara at the target of Brahman so that the arrow and the target i.e. the Atman and the Brahman become one-
प्रणवो धनुःशरो हि आत्मा ब्रह्मतल्लक्ष्यमुच्यते
अप्रमत्येन वेद्धव्यं शरवत् तन्मयो भवेत्
Maandukya Upanishad
Maandukya Upanishad belongs to the Atharvaved. Manduka means a frog. Maandukyopanishad is so called probably because the frog does not have to climb each stair. It can jump from first to the fourth. This Upanishad shows the way to transcend the three stages of jagriti (wakefulness), svapna (dream) and sushupti (sleep) and reach the turiya or the fourth stage which is to become one with Brahman. It’s possible to reach the final stage in one leap, like a frog, by means of worshipping Omkaara. Some say this Upanishad belonged to those tribes who adopted the frog as their symbol. It’s also said that the sage to which this Upanishad was revealed was Varuna in the form of a frog. This is the smallest of all Upanishads with only twelve mantras. This Upanishad claims that the Jeevatma and Paramatma are the same and describes the fourth stage as ‘Shivam Advaitam’
प्रपञ्चोपशमं शान्तं शिवं अद्वैतं चतुर्थं मन्यन्ते स आत्मा स विज्ञेयः
Taittireya Upanishad
Taitireyopanishad belongs to the Krishna Yajurved. It is the most widely studied Upanishad of all. It is named after ‘taittireya’, one of the branches of Krishna Yajurved. It includes 31 sections which are divided into three chapters- shikshavalli, anandavalli/brahmanandavalli and bhriguvalli. ‘Valli’ means a creeper. Shikshavalli deals with the many aspects of imparting education. It teaches the restraints involved in celibacy, the order in which Vedas should be studied, the worship or pranava i.e. Omkaara etc. Famous precepts such as ‘satyam vada’ i.e. speak the truth, ‘dharmam chara’ i.e. follow righteousness, ‘matru devo bhava’ i.e. consider the mother as God etc are found in this Upanishad. The Anandavalli contains the ascending order of bliss which finally culminates in brahmananda or supreme bliss. It contains the reference to the five sheaths out of which our body is made- annamaya kosha (the gross, physical body), pranamaya kosha (the life giving vital force), manomaya kosha (made up of mind), vijnyaanamaya kosha (made up of intelligence or wisdom), anandamaya kosha (innermost covering of pure bliss). Bhriguvalli is what Varuna taught to his son, Bhrigu. It defines Brahman as that from which the universe comes into being, that by which it is sustained, and that into which it is finally merged. He who realizes Brahman fears nothing-
यतो वाचो निवर्तन्ते अप्राप्य मनसा सह
आनन्दो ब्रह्मणो विद्वान् न बिभेति कदाचन
Aitareya Upanishad
Aitareyopanishad appears at the end of the Aitareya Aranyaka of Rigved. It is so called because it came to the world through the sage Itareya. It contains three chapters. This Upanishada deals with how a Jiva (soul) enters the mother’s womb from the father, then is born in the world, takes birth again and again according to sin and merit and how liberation from the vicious cycle of birth and death can be obtained through the realization of the true nature of atma.
Chaandogya Upanishad
Chaandogyopanishad appears in the Chaandogya Brahmana of Samaved. This Upanishad probably gets its name from Chaandogya, the singer. It contains eight chapters. At the beginning, Chaandogyopanishad names Omkaara as the ‘Udgaataa’
It mentions many vidyas or disciplines like akshi vidya, akasha vidya, madhu vidya, sandilya vidya, panchaagni vidya, prana vidya etc. The truth is taught through the medium of many interesting stories.
Brihadaaranyaka Upanishad
‘Brihat’ means vast and as the name goes, the Brihadaranyaka Upanishad is the biggest of all Upanishads. This Upanishad is the entire aranyaka of the Shukla Yajurved. It contains six chapters which are further divided into 3 sections containing two chapters each. The first two are called ‘madhu khanda’, the next two are called ‘muni khanda’ and the last two are ‘khila khanda’. The Brihadaranyakopanishad starts with the mantra- ‘asato ma sat gamaya’. It means- lead me from the destructible to the eternal. It is in this Upanishad that the soul is described negatively as ‘नेति नेति’ i.e. not this, not this or that which cannot be described. This Upanishad concludes by stating the three virtues that one should practice, i.e. self-restraint, giving, and compassion. In this Upanisad, there is a common pattern of a dialogue between a Preceptor and a student or an enquirer.
Basic Philosophical Concepts in Upanishads
Brahman (the absolute)
Brahman is the ‘absolute’, ‘the highest self’, ‘the supreme self’. Brahman is derived from the Sanskrit root ‘brih’ (बृह) meaning to expand. Brahman, thus, means that which is all-pervading. According to the Taittiriya Upanishad, the essential nature of Brahman is ‘satyam’ i.e. real, ‘jnanam’ i.e. knowledge, ‘anantam’ i.e. infinite. The later Vedantic schools described Brahman as ‘sat, ‘chit’ and ananda’ i.e. ‘existence, pure consciousness and pure bliss’. All beings come into existence from Brahman, subsist in Brahman and finally are reabsorbed in Brahman. The Upanishads stipulate two forms of Brahman- Parabrahman and Aparabrahman. Parabrahman is the higher self devoid of form and attributes. Aparabrahman is the lower self with form as well as attributes. The Trinity Brahma, Vishnu and Shiva are the examples of Aparabrahman. Both Parabrahman and aparabrahman are essential for the knowledge of reality.
Atman (the self)
Atman is the soul that resides in the bodies of individuals. It is untarnished by the good or bad deeds of the individual. According to Maandukya Upanishad, the Atman is ‘adrashtaa’ i.e. unperceivable, ‘agraahya’ i.e. ungraspable, ‘avyavahaarya’ i.e. impossible to deal with, ‘achintya’ i.e. not thinkable, ‘alakahana’ i.e. with no distinct mark, and ‘advaiata’ i.e. nondual or one of a kind. Kena Upanishad describes Atman as both ‘jnyeya’ as well as ‘ajnyeya’ which means that the Atman is both knowable as well as unknowable. In the entire Upanishadic literature, the Atman is described as ‘sarvavyaapta’ i.e. all-pervading, ‘sarvajnya’ i.e. omniscient, ‘sarvasaakshi’ i.e. omnipresent, ‘amruta’ i.e. immortal, ‘sarveshvara’ i.e. the supreme lord. Atman is described as being subtler than the subtle and greater than the great. It is neither mobile nor immobile, neither momentary nor permanent, neither tangible nor intangible, neither subtle, nor great. The Atman is above all opposites. It is the substratum of all things. It is a narrower Brahman.
Brahman is the fundamental source of the external world whereas Atman is the inner pure consciousness in man. However, they are not different from each other. The Brihadaranyaka Upanishad says,
स वा अयम् आत्मा ब्रह्मन्
This means ‘Verily, the Brahman is Atman.
According to Max Muller, “Atman and Brahman- the together may be called the two pillars in which rests nearby the whole of the edifice of Indian Philosophy”
Jiva (the individual self)
The word Jiva is derived from the Sanskrit root ‘jiva’ (जीव) meaning to live continuously. The ‘kartaa’ i.e. the doer and the ‘bhoktaa’ i.e. the enjoyer are synonymous with the individual self. It is the Jiva that is subject to the cycle of birth and death (Samsaara), until libration is achieved. Activity and cognition are the prerogatives of Jiva. Jiva faces the joys and sorrows of life, performs good or bad deeds, and bears the fruit of its actions. It is the Jiva that is filled with desires, infatuation, greed and the like. All such activities bind him to this world.
Moksha (liberation)
The word ‘moksha’ is derived from the Sanskrit root ‘mucha’ (मुच्) meaning to release or to liberate. Moksha means to be emancipated from the cycle of birth and death. The ultimate objective of the Jiva, entrapped in the cycle of birth and death, is to be free from the pythonic clutches of the world, by attaining the final release. Moksha consists in realizing the true nature of Atman. To know the true nature of Atman is to become Brahman-
ब्रह्मविद् ब्रह्मा भवति
The Teachings of Upanishads
Many people believe that the Upanishads are the realm of the elderly, who are tired of life. On the contrary, Upanishads make us understand who we actually are. They tell us the truth about ourselves and the world around us. All the Upanishads unanimously proclaim advaita i.e. nondualism. They propound that the world that we perceive around us is a mere illusion (Maya). Our mind is full of desires and hence is enmeshed in Maya’s web. The Upanishads help the individual realize the truth and guide him towards liberation. The Upanishads follow the path of Knowledge to liberate an individual from the cycle of birth and death. They say that the body, mind, intellect and all other things and people that are around us are perishable. The only imperishable substance in this world is the Brahman and Atman. To become one with the Brahman is the ultimate aim of a human being. To recognize Brahman, one needs the eyes of the soul. The physical eyes and the mind are futile in understanding Brahman. The understanding of Brahman is only possible through constant contemplation and meditation on the part of the seeker. Giving up attachment to the worldly stuff, abandoning all selfish desires and forsaking the idea that the world around us is real and eternal, a man should concentrate on Brahman. Thus, a Jiva should give up the worldly ideas, realize that he is, in fact, Atman and his final aim is to merge and become one with the Supreme Reality i.e. the Brahman. The Upanishads preach this through stories or a dialogue format.
The Upanishadic teaching is proficiently told by Adi Shankaracharya in one verse-
श्लोकार्धेन प्रवक्ष्यामि यदुक्तं ग्रन्थकोटिभिः
ब्रह्म सत्यं जगन्मिथ्या जीवो ब्रह्मैव नापरः
It means ‘I will tell the philosophy of a ten million books in half a meter: The Brahman is the supreme reality; the world around us is fake and deceitful; the Atman is nothing but Brahman’
Four Great Sayings of Upanishads
The Vedas have many mahaavaakyas or great sayings. But four- one from each Veda- are very important, thought-provoking and powerful. These spell out the nonduality of Jiva and Brahma. If these are chanted and meditated upon deeply, non-duality could actually be experienced. These four great sayings are contained in the four Vedas.
1) प्रज्ञान ब्रह्म
This great saying is contained in the Aitareya Upanishada of Rigved. It says that exalted actual experience alone is Brahman or ‘Brahman is the Supreme knowledge’.
2) अहं ब्रह्मास्मि
This great saying is from the Brihadaaranyaka Upanishad of Shukla Yajurved. It means ‘I am Brahman’.
3) तत्त्वमसि
This great saying is in the Chaandogya Upanishad of Samaved. It is in the form of a Preceptor teaching his disciple. It means ‘That thou art’ i.e. you are Brahman, the Supreme Reality. The Preceptor enlightens his disciple about his true identity.
4) अयमात्मा ब्रह्म
This great saying is from the Maandukya Upanishad of Atharvaved. It means ‘This soul is Brahman’
Thus, all the four mahavaakyas point out to one single truth- ‘I am verily the Atman and the Atman is nothing but Brahman- the Supreme Reality’.
Vedas vs Upanishads
It might seem strange that Vedas, at the beginning, concentrate on the materialistic aspect of life, and later, in the Upanishads, claim that the world is illusory and that Brahman should be sought. The Vedas contain many Gods whereas the Upanishads speak of one single Brahman. What appears at the beginning of the Veda is negated by it at the end. However, the jnaana kaanda i.e. the Upanishads do not oppose the karma kaanda i.e. the Vedas and vice versa. The karma kaanda exists solely for the purpose of preparing one for Vedanta. The Vedic karmas and worship are of no use, unless they ultimately lead to jnaana or enlightenment. The Puranas say that merely stopping at the stage of Vedic karma is short-sightedness. The Vedic rites should be duly performed, but it should be done without the sense of doership. The Ishavasya Upanishad proclaims-
कुर्वन्नेह कर्मणि जिजीविषेच्छतः समाः एवात्वयिनान्यथेतोsस्ति नकर्मलिप्यतेनरे
The karma kaanda and the jnaana kaanda together form a journey from polytheism to monotheism and from duality to nonduality, which in turn leads to enlightenment.
Other literature inspired by Upanishads
The Upanishads were the first to delve in the truth about life, the falsity of the world and the reality of the Brahman. They speak about the nonduality of the Atman and the Brahman. They preach the mortality of the body and the immortality of the soul.
The Upanishads form a base for many later philosophies and literatures.
The Gita Literature
The Indian sacred books that are termed as Gita talk about God, soul, life, afterlife, pangs of life and death. Gita generally refers to Bhagavad Gita. However, there are about thirty four other Gitas like Ishwar Gita, Ram Gita, Ashtavakra Gita, Avadhuta Gita, Guru Gita, Pandava Gita, Brahman Gita, Vaishnava Gita, Ganesh Gita etc. The Bhagavad Gita is a dialogue between Shri Krishna and Arjun. It talks about the mortality of the body, immortality of the soul and other concepts like duty, righteousness, devotion, liberation etc. Ashtavakra Gita is a dialogue between Sage Ashtavakra and King Janaka on the nature of soul, reality and bondage. The Avadhuta Gita, by Lord Dattatreya, expounds complete nonduality. The Guru Gita is a dialogue between Lord Shiva and Parvati on the importance of a Guru or a Preceptor, who helps us in the realization of Brahman. All the Gita literature preaches a part or the whole of the Upanishads in a songlike way.
The Six Darshanas
The six darshanas or ‘षड्दर्शन’ are the six systems of Indian philosophy. These six systems are concerned with the understanding of the Supreme Being and its relation with the individual soul and the external world. The beginnings of Indian philosophy can be found in the hymns of Rigved and Atharvaved. The Upanishads are the origin of these six Indian philosophies. All of them unanimously believe that the final goal of life is the attainment of reality which is established by philosophical discussions. The six darshanas are- Nyaya, Vaisheshika, Sankhya, Yoga, Meemansa and Vedanta.
Nyaya and Vaisheshika
The Nyaya Darshana and Vaisheshika Darshana are closely related to each other. Sage Gautam was the founder of Nyaya sutras, while Sage Kanad was the founder of Vaisheshika sutras. Both the systems lay stress on methodological reasoning. They explain the origin of the world from atoms. They deal with problems of psychology and aim at the salvation of the soul.
Sankhya
Sage Kapila is said to be the founder of the Sankhya philosophy. Sankhya philosophy is dualistic. It believes in two things- Purusha and Prakruti- both without beginning and end but different from each other. Purusha is the soul, while Prakruti is matter or physical substance and both of them are equally existent. The Sankhya doctrines have their origin in some passages of the Katha, Chandogya and Shvetashvara Upanishads. Buddhism has been greatly influenced by the Sankhya philosophy.
Yoga
The Yoga system is an improvement on the Sankhya philosophy with an additional form of mental ascetism as the most effective means of acquiring knowledge. The Yoga philosophy has its origin in the Vedas, where it is known as Praanavidya. Later on, it was systematized by Sage Patanjali in his Yoga sutras. Yoga is controlling the mind and getting rid of the influence of matter. To gain full control over the functions of the mind (thinking, feeling, memorizing, desiring etc) eight steps are enumerated by Yoga- Yama, Niyama, Asana, Pranayama, Pratyahara, Dharana, Dhyaana and Samadhi.
Meemansa
Jaimini was the author of the Meemansa sutras. Meemansa means ‘inquiry’. It deals with the practical side of the Vedic religion. This system is concerned with the Karma Kanda i.e. Samhita. Brahmana and Aranyaka. Meemansa is also known as ‘karmameemansa’ or ‘poorvameemansa’.
Vedanta
The Vedanta philosophy is entirely based on the Upanishads. After reading the Upanishads, Sage Baadaraayana or Sage Veda Vyasa, understood them to be the fundamental nature of Vedas. He became inspired by them and stated the philosophy in them in the form of sutras. These are known as Vedanta sutras or Brahma sutras. The Vedanta sutras contain 555 sutras which are divided into four chapters- Samanvay, Avirodh, Saadhanam and Phalam. The Vedanta sutras are nothing but the Upanishadic teaching in a compact manner. The Vedanta darshana is also known as Brahmameemansa, Uttarmeemansa or Shaaririkameemansa (inquiry concerning Brahman or the embodied soul).
The famous Vedantist philosopher Shankara (8th century AD) expounded the Vedanta sutras in his commentary known as Shaaririkabhaashyam. It was he who fully elaborated the doctrine of ‘maya’ or the cosmic illusion and established that there is no other existence but Brahman. The same Vedanta sutras were commented on by different persons holding different views. Thus, there came into existence many schools of Vedanta. Following are some of the well known schools-
1. अद्वैतमतम् of Shankaracharya- 8th century AD
2. भेदाभेदमतम् of Bhaskaracharya- 10th century AD
3. विशिष्टाद्वैतमतम् of Ramanujacharya- 11th century AD
4. द्वैताद्वैतम् of Nimbarka- 12th century AD
5. द्वैतमतम् of Anandatirtha or Madhvacharya- 13th century AD
6. शुद्धाद्वैतम् of Vallabhacharya- 15th century AD
7. शैवविशिष्टाद्वैतम् of Shrikantha- 13th century AD
8. अचिन्त्य भेदाभेदबोधकं गोविन्द भाष्यम् of Baladeva- 18th century AD
All the Gitas and Darshanas are not necessarily directly based on the Upanishads. However, the fact remains that the ideals prescribed in them have been inspired by some Upanishadic thought.
The Nobel Prize winner in physics, Erwin Schrodinger, in his book ‘What is life?’ says “In the Western terminology, to say: ‘Hence I am God Almighty’ sounds both blasphemous and lunatic. But please disregard these connotations for the moment and consider whether the above inference is not the closest a biologist can get to proving also their God and immortality at one stroke. In itself, the insight is not new. The earliest records to my knowledge date back some 2,500 years or more. From the early great Upanishads the recognition ATHMAN = BRAHMAN upheld in (the personal self equals the omnipresent, all-comprehending eternal self) was in Indian thought considered, far from being blasphemous, to represent the quintessence of deepest insight into the happenings of the world. The striving of all the scholars of Vedanta was, after having learnt to pronounce with their lips, really to assimilate in their minds this grandest of all thoughts.”
The Upanishads are unique and outstanding with their knowledge and philosophy which is both logical and profound. The Upanishads have influenced many later Indian philosophies. They have even attracted the attention of the Westerners. The Upanishads are, indeed, the true wealth of Indian philosophy and literature.
The German Philosopher, Arthur Schopenhauer, says “It is the most rewarding and the most elevating reading which there can possibly be in the world. It has been the solace of my life and will be of my death”
References
· Sanskrit sahityacha itihas- brahmane- aranyake- upanishade; Dr. Suruchi Pandey; Sanskrit Sanskriti Samshodhika, Dnyanaprabodhini Sadashiv peth, Pune
· The Vedas; Sri Chandrashekhara Saraswati; Bhavan’s Book University
· Isha Upanishad Revisited; N. Srinivasagopalan; Oupanishada Publications
· Ishavasya Upanishad; Prof G. T. Pandya
· A glimpse on Shruti (Vedas and Upanishads); E. T. Sankaran Kutty; Bhavan’s Book University
· Upanishads; C. Rajagopalachari; Bhavan’s Book University
· Sanskrit Sah