Hindu tradition has Tantras coming direct from archaic dialogs between Shiva "Lord of Yoga" and his Shakti, the "Great Goddess." Some of these dialogs got "overheard" or revealed to Yogi Siddhas, whose students eventually wrote them down. The Tantric teachings of Shiva and Shakti come to us from the distant past, perhaps as far back as the Indus Valley civilization, circa 2500 B.C.E. These secret teachings were preserved mostly in oral form, aided by the use of symbols and the sacred arts, such as sculpture, painting, music and dance.
Written Tantras are the latest of the Hindu sacred writings (Shastras), following the Vedas, Upanishads etc. South India has its own tradition of Tantras, also derived from Shiva, Shakti and the lineage of Siddhas. Hindu medical, alchemical and astrological texts are commonly termed Tantras, as are works dealing mainly with sorcery.
Buddhist occult tradition tells that Gautama the Buddha imparted esoteric teachings to select disciples, "by initiation and by word of mouth."
Modern scholars suggest that many of the known early Tantras were "transmitted in utmost secrecy for 300 years or so," passed-on in dialogs between teachers and chosen students. It was not until the time of the Siddhas, circa 6th-11th century C.E., that they were written down. In Mahayana Buddhist culture, study of the Tantras naturally follows after study of the Sutras.
There are Tantras, both Hindu and Buddhist, compiled or created by Yogis, Yoginis, priests or scholars. These are generally based on fragments or compilations of earlier works, oral tradition, mystic songs or are the result of empirical scientific studies in medicine, chemistry, astronomy etc. When a sacred text is called a Tantra, it takes on added significance because of the traditions of lineage, historicity and revelation. Spiritual sex, literal or allegorical, is a topic discussed in many Tantras.
Some Tantras were written on palm-leaves, flimsy folios of paper and never published. Many were lost over the passage of time. Others were "discovered" and entered the mainstream of spiritual literature. These texts were generally regarded as radical, heretical even, but nevertheless viewed as authoritative in the present decadent aeon, the Kali Yuga.
Following is a list of Buddhist and Hindu Tantras, of significance, together with likely dates of their compilation and details of their English translation, if available: SOME BUDDHIST TANTRAS Guhyasamaja Tantra, the Sanskrit text edited with commentaries by Benoytosh Bhattacharya, Gaekwad's Oriental Series, 1934. Dr. Alex Wayman translated selected verses into English, published as Yoga of the Guyasamaja, Motilal, Delhi, 1977. This important "Mother" Tantra was probably compiled in the 4th century C.E.; Manjusri Mula Tantra, edited by T. Ganapati Shastri, Trivandrum Sanskrit Series, vols. 70, 76 and 84, 1920, 1922 and 1925; Chandamaharosana Tantra, chapters I-VIII, translated by Dr. Christopher George, published by the American Oriental Society, New Haven, 1974. Possibly compiled in the 7th century C.E., the earliest manuscript is from around the year 1100; Hevajra Tantra, selected verses translated with substantial commentaries by Dr. David Snellgrove, Oxford University Press, London, 1959. This important text was probably compiled between the 7th and 8th centuries C.E.; Chakrasambhara Tantra, selected verses translated by Lama Kazi Dawa Samdup, Luzac, London, 1910; Mahakala Tantra, translated by Dr. William Stablein. Ph.D. dissertation, Columbia University, 1976.
Abhidhanottara Tantra, partly translated by Dr. Martin Kalff; Samvarodaya Tantra, selected chapters translated by Shinichi Tsuda, Hokuseido Press, Tokyo, 1974; Kalachakra Tantra, a 10th century text, published in Tibetan facsimile and with commentary in English by Dr. Lokesh Chandra, New Delhi, 1966. Also selectively translated by Jeffrey Hopkins and published as Kalachakra Tantra Rite of Initiation, 1985 and Wisdom, Boston, 1989, and extracted in various English formats, including Gelong Jhampa Kelsang's translation of Ngawang Dhargyey's Commentary on the Kalachakra Tantra, Dharamsala, 1985.
There are very many other important Buddhist Tantras, mostly only now available in the Tibetan language. Among them are: the Kurukulla Tantra; Mahavairochana Tantra; Vajrapatala Tantra; Vajrayogini Tantra, Yogini Tantra and others too numerous to detail. The official compilation of Tibetan sacred books, known as the Kanjur and Tenjur, contain 22 volumes of Tantras and 86 volumes of commentaries on them. The Nyingmapa "old" sect of Tibetan Buddhists know of "over a hundred thousand Tantras"! SOME HINDU TANTRAS Mahavidya Tantra, possibly dating from before the 4th century C.E.; Lakshmi Tantra, translated by Sanjukta Gupta, E. J. Brill, Leiden, 1972, compiled sometime between the 9th and 10th centuries C.E.; Kularnava Tantra, compiled around 1000 C.E. Available in English translation.
Kalivilasa Tantra, published by Arthur Avalon (Sir John Woodroofe) in English, 1916; Kalikapurana (Tantra), chapters 54-69 translated by K. R. Van Kooij, E. J. Brill, Leiden, 1972, compiled around the fourteenth century C.E.; Kamaratna Tantra, translated by Hemchandra Tattabhusan, Shillong, 1928; Mahanirvana Tantra, better known as the Tantra of the Great Liberation, translated by Arthur Avalon (Sir John Woodroffe), Calcutta and London, 1913. A very late text, with radical reformist views.
Other important Hindu Tantras, mostly dating from between the 11th and 17th centuries are: Chinnamasta Tantra, Ganapati Tantra, Gandharva Tantra, Guptasadhana Tantra, Jnanarnava Tantra, the Kakachandishvarakalpa Tantra, translated by Jyotir Mitra, Varanasi, 1970, in manuscript; Kali Tantra, Kamakhya Tantra, Kaulavali Tantra, Kubjika Tantra, Kulachudamani Tantra, English translation available on the Internet at the Hindu Tantrik home page; Kularnava Tantra, compiled between the 11th and 15th centuries, translated by Rai, 1993 and selected parts by Goudriaan, 1992; Kundalini Tantra; Malinivijayottara Tantra, translated by V. D. Shastri, Punjab University, 1956; Matrikabheda Tantra; Maya Tantra; Netra Tantra, translation available on the Internet; Nila Tantra; Niruttara Tantra; Nirvana Tantra; Saraswati Tantra; Svacchanda Tantra, an early Shaivite work, partly translated by Teun Goudriaan, SUNY, 1992; Tantraloka; Tantraraja Tantra; Tara Tantra; Todala Tantra, available on the Internet; Vinashikha Tantra, translated by Teun Goudriaan, Motilal, Delhi, 1985; Yogini Tantra and Yoni Tantra, available on the Internet at the Mike Magee "Hindu Tantrik" home page.
There are many other "Kashmiri" Tantras, "Bengali" Tantras (mostly from a relatively late period, into this century) and "South Indian Tantras", which are sometimes referred to as Kalpas.
A Tantra generally is a "no holds barred" guide to spiritual liberation, presumably put together by a liberated enlightened person. The very large number of both Buddhist and Hindu Tantras that have survived in some form or another, suggests that spiritual enlightenment was not as difficult to achieve as is generally supposed.