Mysticism from the Greek (mystikos) "an initiate" (of the Eleusinian Mysteries, (mysteria) meaning "initiation"[1]) is the pursuit of achieving communion or identity with, or conscious awareness of, ultimate reality, the divine, spiritual truth, or God through direct experience, intuition, or insight; and the belief that such experience is an important source of knowledge, understanding, and wisdom. Traditions may include a belief in the literal existence of realities beyond empirical perception, or a belief that a true human perception of the world trancends logical reasoning or intellectual comprehension.

The term "mysticism" is often used to refer to beliefs which go beyond the purely exoteric practices of mainstream religions, while still being related to or based in a mainstream religious doctrine. For example, Kabballah is a significant mystical movement within Judaism, Sufism is a significant mystical movement within Islam, however Gnosticism can refer to either a mystical movement within Christianity or as various mystical sects which arose out of Christianity. Some have argued that Christianity itself was a mystical sect that arose out of Judaism. While Eastern religion tend to find the concept of mysticism redundant, non-traditional knowledge and ritual are considered as Esotericism, for example Buddhism's Vajrayana. Vedanta is considered the mystical branch of Hinduism.

Mystics generally hold that there is a deeper, more fundamental state of existence hidden beneath the appearances of day–to–day living (which may become, to the mystic, superficial or epiphenomenal). For the mystic, the intangible is the focus, and may be perceived in any of various ways — as God, ultimate reality, a universal presence, a force or principle, psychological emancipation — and be experienced or realized directly. Such experiences are spoken of, variously, as ecstatic revelation, theosis, direct experience of the divine or of universal principles, nirvana, enlightenment, satori, samadhi, etc. They are sometimes characterized by a fading or loss of self, or a perceived interconnection with all existence, and are often accompanied by feelings of peace, joy or bliss, as well as severe cultural alienation.

This is a belief in or the pursuit in the unification with the One or some other principle; the immediate consciousness of God; or the direct experience of religious truth. Mysticism is nearly universal and unites most religions in the quest for divinity. It can also be a sense of mystical knowledge. Dionysius the Areopagite was the first to introduce the concept "unknown knowing" to the Western World. In areas of the occult and psychic it denotes an additional domain of esoteric knowledge and paranormal communication. Even though it is thought that just monks and ascetics can become mystics, mysticism usually touches all people at least once in their lives.

Apart from religious mysticism, but not entirely separated from it, is nonreligious mysticism. This is more of an experiencing mysticism through, or from, Nature, although some have discovered God or the Absolute of Nature through such experiences. An authentic experience of mysticism derive from Nature is essentially the unity of the subject and the object. In other words, the person becomes one with Nature; all boundaries or separation between the person and Nature disappears. The person becomes part of nature and is not separate from it.

This is clearly seen in the Goddess religion, which includes neo-Paganism and neo-Pagan Witchcraft, which worships Nature. Such worship includes love where the separation between the subject and object vanishes. Starhawk, in The Spiral Dance, defines it as immanence. Immanence is one of the three core principles of the Goddess religion, the other two being interconnection and community. "Immanence means that the Goddess, the Gods, are embodied, that we are each a manifestation of the living being of the earth, that nature, culture, and life in all their diversity are sacred. Immanence calls us to live our spirituality here in the world, to take action to preserve the life of the earth, to live with integrity and responsibility."