Mysticism, according to its historical and psychological definitions, is the direct intuition or experience of God; and a mystic is a person who has, to a greater or less degree, such a direct experience -- one whose religion and life are centered, not merely on an accepted belief or practice, but on that which the person regards as first hand personal knowledge.

Mystics of the Church (ed. Wipf and Stock Publishers, 2002) - ISBN: 9781579103316