Fr. Egan surveys the current scholarship on mysticism, giving special attention to the work of William James, Richard Bucke, Walter Stace, Erich Neumann, Carl Albrecht, R. C. Zaehner, Evelyn Underhill, Thomas Merton, William Johnston, Teilhard de Chardin, Hans Urs von Balthasar, Harvey Cox, Karl Rahner, Bernard Lonergan, and many lesser-known authors.
The book covers a wide spectrum of modern thinking. It presents authors who treat mysticism as a psychological phenomenon involving pathology and states of consciousness, as well as others who understand it as stages of life toward union with the God of Love. Fr. Egan also highlights both those authors who have opened up Christian mysticism to the riches of the Eastern tradition and those critical of this turn to the East. Finally, he explores the theological reflections of Karl Rahner and Bernard Lonergan for their ability to bring together the mystical spirituality and academic theology. These contemporary theologians offer a solid foundation for a new science of mysticism based on Christian mystical tradition, empirical sciences, East-West dialogue, and modern theological pluralism.