Classification of the Shaiva Canon

The Shaiva canon can be divided as follows:

a. shaivasiddhAnta

b. bhUta and gAruDa tantras

c. vAma tantras

d. bhairava tantras

e. Others - pAshupatas,kapAlikas, kaulas

shaivasiddhAnta

 - The Siddhanta belongs to the Upper current, spoken by the Upper face

 - There are 28 principal siddhAntAgamas and ~200 upAgamas associated with them

 - These texts are largely concerned with worship of sadAshiva in li~nga form

 - Descriptions of the temples, li~nga and iconic forms of the gods and goddesses of the siddhAnta constitute an important part of these Agamas.

 - Details of rituals

 - regular daily rites as well as occasional ones such as consecration ceremonies and festivals

 - initiation of the neophyte into this form of shaivism or the priesthood

 - primarily concerned with ritual and devote relatively little space to philosophical matters or even yoga

 - the philosophical standpoint of these Tantras can, broadly speaking, be said to be a dualism of a more or less tempered form. [The homonymous philosophical school inspired by these Agamas, however, ultimately developed a well defined dualism, according to which there are three basic realities, namely, Siva (pati) the fettered soul (pashu) and the factors that bind it (pAsha). The founder of dualist Saivism was called Amardaka.]

- The Siddhanta flourished in the areas where it spread, until it was devastated by the Muslim invasions, which started in the eleventh century, or supplanted by other forms of Hinduism.

- It survived, however, in South India where it changed its medium of expression from Sanskrit to Tamil in which form it is better known and persists to this day.

bhUta and gAruDa tantra

- belong to the Western and Eastern currents.

- almost entirely lost

- dealt with magical cures (particularly of snakebite), exorcism of malevolent ghosts and spirits,
the protection of children from such entities as well as the acquisition of magical powers and other such matters

vAmatantra

- spoken by the Northern face (not to be confused with left-handed path)

- The only Tantra belonging to this group that has been recovered so far is the viNaashikhatantra

- The dominant form of Siva in these Tantras appears to have been Tumburubhairava. He is described as having four faces, each one of which spoke one of the major Tantras of this group, namely, the
Tantra of the Severed Head (shirashcheda), the Tantra of the Crest of the Vina (viNaashikha), the Tantra of Delusion (saMmohana) and the Tantra of the Higher Law (nayottara).

- this cult did not survive much beyond the eleventh century in either India or south-east Asia

bhairavatantras

- concerned with the worship of Bhairava (literally, the Terrible One)

- it has many sub-cults like mahAkAla bhairava etc

- many of these rituals were originally performed in cremation grounds or lonely places for the
benefit of a few select initiates and many of them involve the offering of meat and wine to the deity and,
at times, ritual intercourse. 

- they were numerous and of varied content and not all of them considered these practices important.

Source: The Doctrine of Vibration by Mark S.G. Dyczkowski