Transcendental Meditation was popularized in the West by Maharishi Mahesh Yogi in the 1960s. This method of meditation is marketed as being thousands of years old and stemming from the Vedic (Hindu) tradition. Although its religious roots are stated, it is more frequently spoken of by the organization in secular terms, as a non-religious form of meditation (i.e. "there's nothing to believe in"). Practitioners often bring their own paradigms to this practice, which may or may not include religious understandings.
The goal of Transcendental Meditation is to still the mind and rest in the "Unified Field," a level of consciousness that is beneath our normal surface level thoughts. Maharishi calls the state of a perfectly stilled mind Pure Consciousness, Bliss Consciousness, or Transcendental Consciousness.
Benefits of Transcendental Meditation reportedly include:
an experience of deep rest and relaxation which reduces stress in day to day life
a feeling of inner peace or fullness within, leading to reduced anxiety
the ability to remain fully present in the moment
mental benefits including increased intelligence, creativity, memory, and "brain coherence"
health benefits including greater energy, improved asthma symptoms, improved sleep, reduction in ADHD symptoms, lower cholestorol, reduction in hypertension, improved symptoms related to diabetes, improved symptoms related to PTSD, etc.
a felt connection to God (for those who interpret TM in religious terms)
Strictly speaking, the true method of Transcendental Meditation supposedly must be taught by a certified instructor (thus preserving the lineage from teacher to student down through time). The closest we get in print to a description from Maharishi himself comes from his Science of Being and Art of Living:
"The process of bringing the attention to the level of transcendental Being is known as the system of Transcendental Meditation. In the practice of Transcendental Meditation, a proper thought is selected and the technique of experiencing that thought in its infant states of development enables the conscious mind to arrive systematically at the source of thought, the field of Being. Thus, the way to experience transcendental Being lies in selecting a proper thought and experiencing its subtle states until its subtlest state is experienced and transcended."
Here's another description by Jack Forem, from probably the most accessible written introduction to TM available – Transcendental Meditation: The Essential Teachings of Maharishi Mahesh Yogi:
"The practice involves thinking – not chanting aloud – a specific sound, called a mantra, chosen for each person at the time of instruction. During TM, the mantra is used as the object of attention. The meditator is not at all concerned with any meaning the sound may or may not have; dwelling on meaning would be a type of contemplation and would keep one's awareness at a more superficial level. It is the sound quality – along with the specific way the mantra is employed – that is conducive to producing the deep rest and refined awareness characteristic of TM..."
Thus, we are never publicly given the full "method." In a typical mantra meditation, the mantra is used as an object of attention and repeated with the breath. When one's thoughts wander away, the meditator simply brings the attention back to the mantra. By this means, the mind is eventually calmed and potentially completely stilled. This is typically how those who have gone through the official TM training describe it. They also often emphasize "effortless thinking" of the mantra.
Many research studies have been performed to evaluate TM's efficacy in a variety of areas and TM is billed as an "evidence-based practice." The David Lynch Foundation lists some of them here. TM.org also has a page with a list of research studies.
Although many interpret Transcendental Meditation in non-religious terms, the Vedic background is clearly present in Maharishi's thought. The correlation between what he calls the "Unified Field," "Pure Consciousness," "Bliss Consciousness," or "Transcendental Consciousness" and what is called in Hinduism "the Atman" or "Brahman" is hard to miss.
In the Vedantic Hindu understanding, at the very core of each human personality lies "the Atman" – a spiritual absolute or "God in us." The Atman lies deeper than what we would call the "personality" or "ego;" it is the Divine core of every created being. The Atman is sometimes referred to as the Higher Self, or simply the Self, and is said to be experienced through deep meditation in which one is taken beyond thought, to the very center of their Being.
The Atman, this Divine core, is sometimes understood to be identical with Brahman – the Spiritual Source of existence, or the Godhead. This is expressed in the Upanishads by the saying "Tat tvam asi": "Thou art That." The Self in each created being is One with the Spiritual Source of existence. This is sometimes referred to as Oneness theology or Monism.
In mystical Hinduism, the goal is to experience and identify oneself with the Atman, leading to "Self-realization," or becoming a channel for God to work through on earth.
The Bhagavad Gita
The Bhagavad Gita is a primary, probably the primary, contemplative text in the Vedic tradition. In it, a type of meditation is described that TM is related to, if not derived from:
"Those who aspire to the state of yoga should seek the Self in inner solitude through meditation. With body and mind controlled they should constantly practice one-pointedness, free from expectations and attachment to material possessions.
Select a clean spot, neither too high nor too low, and seat yourself firmly on a cloth, a deerskin, and kusha grass. Then, once seated, strive to still your thoughts. Make your mind one-pointed in meditation, and your heart will be purified. Hold your body, head, and neck firmly in a straight line, and keep your eyes from wandering. With all fears dissolved in the peace of the Self and all desires dedicated to Brahman, controlling the mind and fixing it on me, sit in meditation with me as your only goal. With senses and mind constantly controlled through meditation, united with the Self within, an aspirant attains nirvana, the state of abiding joy and peace in me.
Arjuna, those who eat too much or eat too little, who sleep too much or sleep too little, will not succeed in meditation. But those who are temperate in eating and sleeping, work and recreation, will come to the end of sorrow through meditation. Through constant effort they learn to withdraw the mind from selfish cravings and absorb it in the Self. Thus they attain the state of union.
When meditation is mastered, the mind is unwavering like the flame of a lamp in a windless place. In the still mind, in the depths of meditation, the Self reveals itself. Beholding the Self by means of the Self, an aspirant knows the joy and peace of complete fulfillment. Having attained that abiding joy beyond the senses, revealed in the stilled mind, he never swerves from eternal truth. He desires nothing else, and cannot be shaken by the heaviest burden of sorrow.
The practice of meditation frees one from all affliction. This is the path of yoga. Follow it with determination and sustained enthusiasm. Renouncing wholeheartedly all selfish desires and expectations, use your will to control the senses. Little by little, through patience and repeated effort, the mind will become stilled in the Self.
Wherever the mind wanders, restless and diffuse in its search for satisfaction without, lead it within; train it to rest in the Self. Abiding joy comes to those who still the mind. Freeing themselves from the taint of self-will, with their consciousness unified, they become one with Brahman.”
The biggest critique brought against the TM movement is that, even if it is technically taught under a non-profit organization, it feels like a business. It currently costs $1,500 to take the introductory course, be given your unique mantra, and taught how to use it properly. Related to the secrecy in method is secrecy in the TM-Sidhi program, in which one can apparently, for an extra fee, be taught how to levitate (sidhi is a word that means something along the lines of "psychic powers"). Click here for one person's experience of this program.
These critiques don't necessarily undermine the Transcendental Meditation technique or its potential positive effects, but might lead to reservations about the Maharishi Foundation itself.
The David Lynch Foundation
The David Lynch Foundation is a non-profit organization founded by the film director David Lynch. The Foundation teaches Transcendental Meditation to "at-risk populations" in schools, correctional facilities, homeless shelters, and to those dealing with post-traumatic stress disorder. The relationship between the David Lynch Foundation and the Maharishi Foundation is unclear.
TM enjoys a host of celebrity endorsements. Prominent meditators include Russell Brand, Jerry Seinfeld, Oprah Winfrey, Ellen Degeneres, Jennifer Aniston, Jeff Bridges, the Beatles, Sheryl Crow, Cameron Diaz, Clint Eastwood, Heather Graham, Hugh Jackman, and Moby among others.