Transcendental Meditation (TM) refers to a specific form of mantra meditation called the Transcendental Meditation technique, and less commonly to the organizations that consitute the Transcendental Meditation movement. Maharishi Mahesh Yogi (1918–2008) introduced the TM technique and TM movement in India, in the mid-1950s.

The TM technique involves the use of a sound or mantra, and is practiced for 15–20 minutes twice per day. It is taught by certified teachers through a standard course of instruction, which costs a fee that varies by country. According to the Transcendental Meditation movement, it is a method for relaxation, stress reduction, and self-development. Varying views on whether the technique is religious or non-religious have been expressed including by sociologists, scholars, and a New Jersey court case.

Technique
The meditation practice involves the use of a mantra and is practiced for 15–20 minutes twice per day while sitting with one's eyes closed. It is reported to be one of the most widely practiced, and among the most widely researched, meditation techniques, with hundreds of published research studies. The technique is made available worldwide by certified TM teachers in a seven-step course, and fees vary from country to country. Beginning in 1965, the Transcendental Meditation technique has been incorporated into selected schools, universities, corporations, and prison programs in the US, Latin America, Europe, and India. In 1977 a US district court ruled that a curriculum in TM and the Science of Creative Intelligence (SCI) being taught in some New Jersey schools was religious in nature and in violation of the First Amendment. The technique has since been included in a number of educational and social programs around the world.

The Transcendental Meditation technique has been described as both religious and non religious, as an aspect of a new religious movement, as rooted in Hinduism, and as a non-religious practice for self-development. The public presentation of the TM technique over its 50-year history has been praised for its high visibility in the mass media and effective global propagation, and criticized for using celebrity and scientific endorsements as a marketing tool. Advanced courses supplement the TM technique and include an advanced meditation program called the TM-Sidhi program.
 

Information Source: https://en.wikipedia.org