Meditation.
Meditation describes a state of concentrated attention on some object of thought or awareness. It usually involves turning the attention inward to the mind itself. Meditation is often recognized as a component of Eastern religions, where it has been practiced for over 5,000 years. It has also become mainstream in Western culture. It encompasses any of a wide variety of spiritual practices which emphasize mental activity or quiescence. Meditation can be used for personal development, or to focus the mind on God (or an aspect of God).
Most traditions address the integration of mind, body, and spirit (this is a major theme of the Bhagavad-Gita); or that of spiritual practice with family life, work, and so on. Often, meditation is said to be incomplete if it doesn't lead to positive changes in one's daily life and attitudes. In that spirit some Zen practitioners have promoted "Zen driving," aimed at reducing road rage.

Meditation is often presented not as a "free-standing" activity, but as one part of a wider spiritual tradition. Nevertheless, many meditators today do not follow an organized religion, or do not consider themselves to do so faithfully. Religious authorities typically insist that spiritual practices such as meditation belong in the context of a well-rounded religious life that may include ritual or liturgy, scriptural study, and the observance of religious laws or regulations.

Perhaps the most widely-cited spiritual prerequisite for meditation is an ethical lifestyle. Many martial arts teachers urge their students to respect parents and teachers, and inculcate other positive values. Some traditions incorporate "crazy wisdom" or intentionally transgressive acts, in their sacred lore if not in actual practice: Sufi poets (e.g. Rumi, Hafiz) celebrate the virtues of wine, which is forbidden in Islam.

Most meditative traditions discourage drug use. Exceptions include some forms of Hinduism and the Rastafari movement, which have a long tradition of cannabis using renunciates; and certain Native American traditions, which use peyote, ayahuasca, or other restricted substances in a religious setting.

A number of meditative traditions requires permission from a teacher or elder, who in turn has received permission from another teacher, and so on, in a lineage. Most Chinese traditions rely on the Confucian concept of a Sifu. Hinduism and Buddhism stress the importance of a spiritual teacher (Sanskrit guru, Tibetan lama). Orthodox Christianity has "spiritual elders" (Greek gerontas, Russian starets); Catholic religious have spiritual directors.

The immediate meditative environment is often held to be important. Several traditions incorporate cleansing rituals for the place where one meditates, and others offer instructions for an altar or other accessories.
Different spiritual traditions, and different teachers within those traditions, prescribe or suggest different physical postures for meditation. Most famous are the several cross-legged postures, including the Lotus Position.

Many meditative traditions teach that the spine should be kept "straight" (i.e. that the meditator should not slouch). Often this is explained as a way of encouraging the circulation of what some call "spiritual energy," the "vital breath", the "life force" (Sanskrit prana, Chinese qi, Latin spiritus) or the Kundalini. In some traditions the meditator may sit on a chair, flat-footed (as in New Thought); sit on a stool (as in Orthodox Christianity); or walk in mindfulness (as in Theravada Buddhism).

Various hand-gestures or mudras may be prescribed. These can carry theological meaning or according to Yogic philosophy can actually affect consciousness. For example, a common Buddhist hand-position is with the right hand resting atop the left (like the Buddha's begging bowl), with the thumbs touching.

Quiet is often held to be desirable, and some people use repetitive activities such as deep breathing, humming or chanting to help induce a meditative state. Practitioners of the Soto Zen tradition meditate with their eyes open, facing a wall, but most schools of meditation assume that the eyes will be closed or only half-open.

Often such details are shared by more than one religion, even in cases where mutual influence seems unlikely. One example would be "navel-gazing," which is apparently attested within Eastern Orthodoxy as well as Chinese qigong practice. Another would be the practice of focusing on the breath, which is found in Orthodox Christianity, Sufism, and numerous Indic traditions.

Sitting cross-legged (or upon one's knees) for extended periods when one is not sufficiently limber, can result in a range of ergonomic complaints called "meditator's knee".

Frequency and duration
These vary so greatly that it is difficult to venture any general comments. On one extreme there exist monks and nuns whose whole lives are ordered around meditation; on the other hand, one-minute meditations are not out of the question.

Twenty or thirty minutes is broadly accepted as being a typical duration. Experienced meditators often find their sessions growing in length of their own accord. Observing the advice and instructions of one's spiritual teacher is generally held to be most beneficial.

Many traditions stress regular practice. Accordingly, many meditators experience guilt or frustration upon failing to do so. Possible responses range from perseverance to acceptance. Also, many meditators stress the importance of continual practice in order to strengthen concentration for prolonged meditation sessions as well as increased focus during their daily lives.

Purposes and effects of meditation
Main article: Health applications and clinical studies of meditation
The purposes for which people meditate vary almost as widely as practices. Meditation may serve simply as a means of relaxation from a busy daily routine; as a technique for cultivating mental discipline; or as a means of gaining insight into the nature of reality, or of communing with one's God. Many report improved concentration, awareness, self-discipline and equanimity through meditation.

Many authorities avoid emphasizing the effects of meditation — sometimes out of modesty, sometimes for fear that the expectation of results might interfere with one's meditation. For theists, the effects of meditation are considered a gift of God or from the Holy Spirit/Ghost, and not something that is "achieved" by the meditator alone, just as some say that a person will not convert to Christianity without the influence of the Holy Spirit/Ghost's presence.

Commonly reported results from meditation include:
Greater faith in, or understanding of, one's religion or beliefs
An increase in patience, compassion, and other virtues and morals or the understanding of them
Feelings of calm or peace, and/or moments of great joy
Consciousness of sin, temptation, and remorse, and a spirit of contrition.
Sensitivity to certain forms of lighting, such as fluorescent lights or computer screens, and sometimes heightened sense-perception.
Surfacing of buried memories.
Experience of spiritual phenomena such as kundalini, extra-sensory perception, or visions of deities, saints, demons, etc.
Some traditions acknowledge that many types of experiences and effects are possible, but instruct the meditator to keep in mind the spiritual purpose of the meditation, and not be distracted by lesser concerns. For example, Mahayana Buddhists are urged to meditate for the sake of "full and perfect enlightenment for all sentient beings" (the bodhisattva vow). Some, as in certain sects of Christianity, say that these things are possible, but are only to be supported if they are to the glory of God.