What is Tantra?

Tantra has no quick easy definition, it is a Sanskrit* word with many meanings, these are a few:
web, extend, expand, weave, thread, a system, a theory, doctrine, any non vedic doctrine, a section in a book, treatise on a given subject, a scientific work, medical text, a mystic work or a mystic teaching such as the dialog between Parvati and Shiva, and a restaurant on Sunset Blvd.

The meanings we will be using are the non-vedic doctrines, mystic works and mystic teachings. This represents the many variations of tantric spiritual practice and belief, all of these fall within what came to be called the Cult of Ecstasy.
This ecstatic cult saw the world as a living, breathing manifestation and celebration of the divine. Tantrics felt and sanctified the magic of life in everything and everyone, seeing the entire universe in the smallest insect. They honored and experienced the body as sacred and divine, its desires and sensual pleasures being tools of transformation and liberation. Tantra was an ecstatic and joyous 'Yes' as opposed to the rule bounded brahmanical "No". Tantra's, 'it's all good', attitude and rejection of the slave like caste system, defied the patriarchal and orthodox Brahmin(Priests)caste who believed the world an illusion/maya, and the body and its desires something to be denied, repressed and conquered.

As large and potent as the universe outside,
Even so large and potent in the universe within our being.
Within each of us are heaven and earth,
the sun and moon, lightening and all the myriad of stars.
Everything in the macrocosm is in this our microcosm.
-Chandogya Upanishads

Tantra is the last living goddess religion, and even today, thousands of years later, tantra's life affirming, female honoring and sex positive, no priest needed,
practices and beliefs raise eyebrows, infuriate and incite colorful outrage with the more god/male based, philosophical and religious teachers.

Tantra is an open source system, or maybe we could say that 'open source, is a tantric system, it grows and expands with participation. And this is at the heart of tantric systems, they are maps to an open participation in life. The numerous, and very often outright contradictory paths of tantra, reflect the multi-faceted, all embracing, interconnected web and ever evolving nature of tantra and the tantric mindset. Tantric systems range from elaborate and ritualistic to sahaja-the spontaneous and zen like approach that has no prescribed system, and everything in between. The texts that describe these ancient body positive practices are known as tantras. Tantric systems and practice have their roots in the matriarchal Indus River civilization, and over time Tantra has extended, expanded and woven its way into Buddhism, Hinduism, Jains, Sufism and the Shingon sect of Japan.

Tantra is alive and well today in India, the West and other parts of the world. A few white Tantric systems are commonly practiced in the West under the names hatha yoga, 3HOkundalini yoga and transcendental meditation to name a few. The more esoteric branches are also available as well as the myriad of California's Osho inspired teachers. The very controversial Osho(Bhagvan Shree Rajneesh) of the 1960's and 70's, promoted a sahaja style tantra that people love or hate, and that is all I will say about Osho.

*Sanskrit and English are in the same family of languages