Christian mysticism arises when the Lord calls some people to a special life of contemplation that frequently includes mystical encounters with Him.
Much of the time this takes the form of a call to monastic life – though not necessarily. Such a life requires great humility, discipline, and commitment to prayer, and in many cases, such as those of St. Theresa of Avila and St. John of the Cross, it is a call to mystical surrender.
The three major stages of mystical life – the purgative, illuminative, and unitive – are described in detail by these two authors as well as contemporary mystics and scholars of mystical life.
To read Fr. Spitzer's article on the stages of Christian mysticism, click here.