Mysticism (from the Greek lang: μυστικός, mystikos, an initiate of a mystery religion) is the pursuit of communion with, identity with, or conscious awareness of an ultimate reality, divinity, spiritual truth, or God through direct experience, intuition, or insight. Mysticism usually centers on a practice or practices intended to nurture that experience or awareness. Mysticism may be dualistic, maintaining a distinction between the self and the divine, or may be nondualistic. Differing religious traditions have described this fundamental mystical experience in different ways:

• Nullification and absorption within God's Infinite Light (Chassidic schools of Judaism)
• Complete detachment from the world (Kaivalya in some schools of Hinduism, including Sankhya and Yoga; Jhana in Buddhism)
• Liberation from the cycles of Karma (Moksha in Jainism and Hinduism, Nirvana In Buddhism)
• Deep intrinsic connection to the world (Satori in Mahayana Buddhism, Te in Taoism)
• Union with God (Henosis in Neoplatonism and Theosis in Eastern and Catholic Christianity, Brahma-Prapti or Brahma-Nirvana in Hinduism)
• Innate Knowledge (Irfan and fitra in Islam)
• Experience of one's true blissful nature (Samadhi or Svarupa-Avirbhava in Hinduism)

Enlightenment or Illumination are generic English terms for the phenomenon, derived from the Latin illuminatio (applied to Christian prayer in the 15th century) and adopted in English translations of Buddhist texts, but used loosely to describe the state of mystical attainment regardless of faith.

Mystic traditions generally form sub-currents within larger religious traditions - such as Kabbalah within Judaism, Sufism within Islam, Vedanta and Kashmir Shaivism within Hinduism, Christian mysticism within Christianity - but are often treated skeptically and sometimes held separately, by more orthodox or mainstream groups within the given religion, due to the emphasis of the mystics on direct experience and living realization over doctrine. Mysticism is sometimes taken by skeptics or mainstream adherents as mere obfuscation, though mystics suggest they are offering clarity of a different order or kind. In fact, a basic premise of nearly every mystical path, regardless of religious affiliation, is that the experiences of divine consciousness, enlightenment and union with God that are made possible via mystical paths, are available to everyone who is willing to follow the practice of a given mystical system. Within a given mystical school, or path, it is much more likely for the mystical approach to be seen as a divine science, because of the direct, replicable elevation of consciousness the mystical approach can offer to anyone, regardless of previous spiritual or religious training.

Some mystic traditions can exclude the validity of other traditions. However, mystic traditions tend to be more accepting of other mystic traditions than the non-mystical versions of their traditions. This is based on the premise that the experienced divinity is able to bring other mystics to their own tradition if necessary. Some, but not all, mystics are even open to the idea that their tradition may not be the most practical version of mystic practice.