The time has come to rewrite mystical theology for the men and women of the twenty-first century. The time has come to restore it to its honored place in the curriculum of theological studies. However, it cannot be taught to the twenty-first century just as it was taught to the fourth and to the sixteenth centuries. It must be renewed and updated; it must be made relevant. The challenge confronting us is to be true to the Gospel and tradition while facing the unique problems that have arisen in the twentieth century.
— William Johnston, Mystical Theology