Thomas Merton (1915-1969) was one of the most influential religious writers of the twentieth century. His The Seven Storey Mountain (1948) is his spiritual autobiography, describing his early doubts, his conversion to Catholicism, and his decision to become a Trappist monk.

The Tao of Physics (1975), by Fritjof Capra, explores some of the striking parallels between modern theories of physics and the mystical traditions of the East.

Jacob Boehme (1575-1624) was a shoemaker in Germany who had spontaneous experiences of divine illumination and became one of the greatest mystics in the Christian tradition. His The Way to Christ, originally written in 1622 and published by Paulist Press in 1978, presents the essence of his thought.

The Interior Castle was written by Teresa of Avila in 1577 and published in the Classics of Western Spirituality series in 1988. The Spanish saint describes the mystical life in terms...