Modern Spiritual Masters is a 12-book series with 12 released primary works first released in 1970 with contributions by Mahatma Gandhi, Henri J.M. Nouwen, Charles de Foucauld, Pierre Teilhard de Chardin, Thich Nhat Hanh, Edith Stein, John Sullivan, Alfred Delp, Thomas Merton, Dorothee Sölle and 4 others.