Atharvaveda (Sanskrit: अथर्ववेद, atharvavéda, a tatpurusha compound of atharvān, a type of priest, and veda meaning "knowledge") is a sacred text of Hinduism, and one of the four Vedas, often called the "fourth Veda". According to tradition, the Atharvaveda was mainly composed by two groups of rishis known as the Bhrigus and the Angirasas. Additionally, tradition ascribes parts to other rishis, such as Kauśīka, Vaśīṣṭha and Kashyapa. There are two surviving recensions (śākhās), known as Śaunakiya (AVS) and Paippalāda (AVP). The Atharvaveda, while undoubtedly belonging to the core Vedic corpus, in some ways represents an independent parallel tradition to that of the Rigveda and Yajurveda.

The Jaina and Buddha texts are considerably more hostile to the AV (they call it Aggvāna or Ahavāna Veda) than they are to the other Hindu texts. The Atharva Veda is less predominant than other Vedas, also the Gayatri mantra used in Atharva Veda is different from other three Vedas. A special initiation of Gayatri is required to learn the Atharva Veda. The Hindus believe the mantras are highly powerful, the Atharvan Pariśiśhthas (appendices) themselves state that specific priests of the Mauda and Jalada schools should be avoided or strict discipline should be followed as per the rules and regulations set by the Atharva Veda. It is even stated that women associated with Atharvān may suffer from abortions if pregnant women remain while the chants for warfare are pronounced. The Atharvaveda is considered by many to be a dark and mystic science, pertaining to the spirits and the afterlife.

Recessions: The Caraṇavyuha (attributed to Shaunaka) lists nine shakhas or Schools of the Atharvaveda:

paippalāda
stauda
mauda
śaunakiya
jājala
jalada
brahmavada
devadarśa
chāraṇavidyā

Of these, only the Śaunakiya (AVS) and the Paippalāda (AVP) recensions have survived. The core Paippalāda text is considered earlier than the Śaunakiya, but both also contain later additions and corruptions. In places where the Śaunakiya and the Paippalāda agree, it is likely the original version. Often, the two recensions in corresponding hymns have a different verse order, or either has additional verses missing from the other. Additionally, from the Viṣṇu and Vāyu Puranas (older Hindu texts on the gods, goddesses and their histories) it may be possible to glean a few more ancient schools that were not listed in the Caraṇavyuha. These are:

sumantu, kabandha, kumuda, śaulkāyana, babhravya, munjakeśa, saindhavāyana, nakśatrakalpa, śāntikalpa,
saṃhitāvidhi

At least some of these may have evolved into the other schools mentioned in the Caraṇavyuha list. Saṃhitāvidhi, Śāntikalpa and Nakśatrakalpa are the five kalpa texts adduced to the Śaunakiya tradition and not separate schools of their own. From the Puranic text we may propose the following evolutionary history of the AV recensions:

vyāsa parāśarya *
|
sumantu
|
kabandha ātharvan-añgirasa
|
+---- pathya
| |
| +---- kumuda
| | | (?)
| | +---- jalada
| +---- jājala
| +---- śaunakiya
| |
| +---- babhravya
| |
| +---- saindhavāyana
| | (?)
| +---- munjakeśa
+---- devadarśa
|
+---- mauda
+---- paippalāda
| | (?)
| +---- stauda
+---- śaulkāyana
+---- brahmavada
| (?)
+---- chāraṇavidyā
Vyasas: Highest Gurus in India.
Parasara: Vedic Rishi, narrator of Vishnu Purana.

There are two main circum-vedic texts associated with the AV, the vaitāna sūtra and the kauśika sūtra. These serve the same purpose as the vidhāna of the Rigveda and are of greater value in studying the Puranic-Vedic link than the AV text itself. There are several Upanishads that are associated with the AV, but appear to be relatively late additions to the tradition. The most important amongst these are the munḍaka and the praṣna Upanishads. The former contains an important reference to Śaunaka, the founder of the Shaunakiya shakha, the latter one is associated with the Paippalāda shakha.

The AV is the first Indic text dealing with medicine. It identifies the causes of disease as living causative agents such as the yatudhānya, the kimīdi, the kṛimi and the durṇama. The atharvāns seek to kill them with a variety of drugs in order to counter the disease (see XIX.34.9). This approach to disease is surprisingly advanced compared to the trihumoral theory developed in the puraṇic era. Remnants of the original atharvānic thought did persist in the puraṇic era as can be seen in suṣruta's medical treatise (garuḍa purāṇa, karma kāṃḍa - chapter: 164). Here following the atharvān theory the puraṇic text suggests germs as a cause for leprosy. In the same chapter suṣruta also expands on the role of helminths in disease. These two can be directly traced back to the AV saṃhita. The hymn AV I.23-24 describes the disease leprosy and recommends the rajanī auṣadhi for its treatment. From the description of the auṣadhi as black branching entity with dusky patches, it is very likely that is a lichen with antibiotic properties. Thus the AV can stake a claim to being one of the earliest texts to record uses of the antibiotic agents.

The AV also informs us about warfare. A variety of devices such as the an arrow with a duct for poison (apāskambha) and castor bean poison, poisoned net and hook traps, use of disease spreading bugs and smoke screens find a place in the AV saṃhita (eg. hymns IX .9, IX.10, the triśaṃdi and nyārbudi hymns). These references to military practices and associated kśatriya rites were what gave the AV its formidable reputation. In the Mahabharata era that shortly followed after the end of the atharvān period there is a frequent comparison between weapons and the mantras of the heroes. Probably, this comparison was initially supposed to mean the application of deadly weapons as mentioned in the atharvān tradition.

Several rituals of the Aryans are a major concern of the AV, just as in the three other vedas. The major rituals covered by the AV are marriage in kāṃḍa - XIV and the funeral in kāṃḍa - XVIII. There are also hymns that are specific to rituals of the bhṛigu-agnirasas, vṛātyas and kśatriyas. One of the most important of these rites is the Viśhāsahi Vrata, performed to invoke the īṃdra and Viṣṇu with the mantras of the XVIIth kāṃḍa. The Vṛātya rituals were performed by individuals who took on a nomadic ascetic way of living and were generally sent into neighboring states by the ruler of a particular state. They appear to have served a role in reconnaissance and negotiations with neighboring states. Finally, there are some rituals aimed at the destruction of the enemies (Abhichārika hymns and rites) particularly using the closing mantras of the XVIth kāṃḍa. Moreover, Abhichārika rites were an integral part of the Vedic as amply attested in the brāhmaṇa literature (see the tale of Yavakrdḍa in the Jaiminiya brāhmaṇa). Thus the AV as such began fully within the classic vedic fold, though it was more specific to certain clans of fire priests. The development of the Abhichārika rites to their more 'modern' form was seen only in the vidhāna literature and in fact began within the Rigvedic tradition in the form of the ṛigvidhāna. The author of the ṛigvidhāna provides passing reference to the development of similar rites in the AV tradition (the references to the Agnirasa Krityās). These rites reached their culmination in the Kauśika and Vaitana Sūtra and in some of the Pariśiśhthas of the atharvān literature. However, these are far removed from the actual hymns themselves suggesting that they represent an encrustation on the atharvanic practice rather than its original form. While in its most extreme form Atharvanic Abhichārika faded away, it did seed the mainstream Hindu culture resulting in the origin of the Puranic form of the fire ritual (yaga-s). It also provided the launching pad for the worship of late evolving popular deities like Kumara and Ganapati to capture the mainstream Hindu ritual.

Philosophical excursions: The AV made the most important contributions to Aryan philosophical thought of all the Saṃhitās. One of the most spectacular expressions of this is seen in the hymn XII.I, the Hymn to goddess Earth or the Pṛithvī Sūktam used in the Aghrāyana rite. The foundations of Vaiṣeśīkā, the highest of the Hindu Darśanas is expressed in the mantra XII.1.26 in which the atoms (Pāmsu) are described forming the stone, the stones agglutinating to form the rocks and the rocks held together to form the Earth. An early pantheistic thought (somewhat convergent to the latter day Viṣiśthadvaitins) is seen in the hymn X.7 that describes the common thread running through all manifest and un-manifest existence as the skaṃbha. This skaṃbha is described as what poured out of the Hiranya Garbha, that was the precursor of the complex world in a very simple form (X.7.28). (Hiranya Garba = " The radiant or golden egg or womb. Esoterically the luminous 'fire mist' or ethereal stuff from which the Universe was formed.")

This Skambha is Indra and Indra is the Skambha which describes all existence. The hymn also describes a pantheistic nature of the Vedic gods (X.7.38): skaṃbha is the heat (tāpaḥ) that spreads through the universe (Bhūvana) as waves of water; the units of this spreading entity are the gods even as branches of one tree. This one theme that repeatedly presents itself in various interpretations that abounded in later Hindu philosophies and can be considered one of the most fundamental expression of Vedic thought.

From internal astronomical references, it has been surmised that the Atharvanic period included the time when the Pleiades occupied the spring equinox (roughly 2200 BC). Further, tradition suggests that paippalāda, one of the early collators, and Vaidharbhī, one of the late contributors associated with the Atharvanic text, lived during the reign of prince Hiranyanabha of the Ikshvāku dynasty, interpreted to mean that the core AV composition was at least complete by 1500 BC.

While these approaches are not widely accepted as valid, it is clear that the core text of the AV is not particularly recent in the Vedic Saṃhitā tradition, and falls within the classical Mantra period of Vedic Sanskrit in the late 2nd millennium BC - roughly contemporary with the Yajurveda mantras, the Rigvedic Khilani, and the redaction of the Sāmaveda.

The Atharvaveda is also the first Indic text to mention Iron (as śyāma ayas, literally "black metal"), so that scholarly consensus dates the bulk of the Atharvaveda hymns to the early Indian Iron Age, corresponding to the 12th to 10th centuries BC or the early Kuru kingdom. During its oral tradition, however, the text has been corrupted by later additions considerably more than the other Vedas, and it is only from comparative philology of the two surviving recensions that we may hope to arrive at an approximation of the original reading.