The great modern yogins
Brought into America as early as the 1890s by the great yogin and disciple of Ramakrishna, Swami Vivekananda, Yoga has also been transported in the arms of many other great yogins and formed into stratified schools seeking to propogate Yoga in its great spiritual context. But these teachers have made their imprint in both India and America, and continue to serve as modern embodiments of Yoga.
Swami Rama Tirtha, who came from a deep yoga tradition in the Himalayas of India, was the founding spiritual head of the Himalayan Institute. He was the first yogin to come to America and be subjected to the scrutiny of modern science. Among other things, he stunned doctors by stopping the beat of his heart completely for several minutes.
Many modern schools of Hatha Yoga derive from the school of Sri Tirumalai Krishnamacharya, who taught in Mysore, India from 1931 until his death in 1993. Among his students prominent in popularising Yoga in the West were Sri K. Pattabhi Jois, B.K.S. Iyengar, Indra Devi and Krishnamacharya's son T.K.V. Desikachar. Desikachar founded the Krishnamacharya Yoga Mandiram in Madras (now Chennai), with the aim of
making available the heritage of yoga as taught by Krishnamacharya.
Other great yogins are Paramahamsa Yogananda, who arrived in America as a powerful example of the universality of Yoga. Sporting a cross, he came to the U.S. with the Bhagavad Gita in one hand and the New Testament in the other, speaking to his disciples in pluralist ideology with Yoga as the binding force.
Aurobindo Ghosh was an intellectual heavyweight from West Bengal. His masterful translations and interpretations of Yoga and Yogic scriptures are authoratative. Beyond this, his personal life, which included over two decades of isolation in the Himalayas practicing yoga, is a fascinating testimony of the life of a true yogin. Besides his influence and scholarly writing on Yoga, he also left his Pondicherry school (near Goa, in India), that continues to investigate and propogate the practice of Yoga.
Gopi Krishna was a Kasmiri office worker and spiritual seeker who was born in 1903, and wrote autobiographical accounts of his spiritual experiences with Yoga. His most famous one is "Kundalini: Path to Higher Consciousness." Gopi Krishna's graphic accounts of his experiences stand out as among the clearest journals documenting a spiritual transformation. They are highly recommended as reading for anyone interested in Yogic phenomena.
Yoga, while its roots are certainly based largely in Hindu philosophy, influenced a good deal by Buddhism as well, is a universal practice. It enjoins the practicer to pursue his or own path to enlightenment, depending on personality and inclination. For this reason, it is easy for the Christian, as a good example, to see Jesus Christ as his or her own ishwar-devata. "Christ the Yogi" is not an uncommon concept in the world Yoga today, and most religions, when viewed through their ethical and spiritual standpoints without the trappings of dogma, are easily reconcilable with Yoga as philosophy in general. Besides this, Yoga can be readily approached without the influence of religion, due to its transcendental message. Yoga has become something that, for the West, captures the essence of "spirituality" and continues to inspire and help many today.
While these and other teachers' influences are deeply inscribed into the surface of the modern yogic ethos, both in India and America, a proliferation of 'yoga clinics' and non-spiritual yoga systems has been seen in the West, especially in the United States. While many Americans view it as an excercise system that simply enhances one's health, a much greater number in India (and a minority in America) still see it as it has been for over 5,000 years, whether in the Bhagavad Gita, the Yoga Sutras, the writings of the Dalai Lama, or the "Yoga Boom" of the twentieth century, a system of spirituality universal in its application.
Some modern styles of Yoga popular in America:
Tantra
While the Bhagavad Gita, Yoga Sutras and Hatha Yoga Pradipika are clearly founded on Upanishadic and Brahmanical thought, much of Yoga has been influenced by and expanded into Tantra. Tantra is more ritual based, having its roots in the first millenium CE, and incorporates much more of a deist base. Almost entirely founded on Shiva and Shakti worship, Tantra visualizes the ultimate Brahman as Param Shiva, manifested through Shiva (the passive, masculine force of Lord Shiva) and Shakti (the active, creative feminine force of his consort, variously known as Ma Kali, Durga, Shakti, Parvati and others). It focuses on the kundalini, a three and a half-coiled 'snake' of spiritual energy at the base of the spine that rises through the chakras until union between Shiva and Shakti (aka samadhi) is achieved.
It views the body as means, rather than as obstruction, to understanding, and as such incorporates mantra (Sanskrit prayers, often to gods, that are repeated), yantra (complex symbols representing Shakti in her various forms through intricate geometric figures) and rituals that range from simple murti (statue representations of deities) or image worship to meditation on a corpse! While much tantra certainly, through its many texts (see kaularvatantra, mahanirvana tantra) and teachers (e.g. Abhinava Gupta, Ramakrishna [a saint who practiced tatnra], etc.) seems odd and highly arcane at times, it is transparent as being completely yogic. Also, injunctions are made that most people are not suitable for Tantra, especially those of pashu-bhava (animal disposition). This implies that anyone who has not observed celibacy, honesty, respect of elders, bodily cleansing, ritual cleansing through prayer, and various other processes for upto twelve years at a time, and still retains base desires, greeds, sexual motivations, etc. one is not fit to practice Tantra. For this reason, even more stringently than other Yogas, Tantra, both Hindu and Buddhist, remains a strictly Guru-initiated system that as yet finds few true adepts outside of India.