The American Trappist monk Thomas Merton wrote extensively about inner life and mysticism. His dialogue with spiritual practicioners and authors from various traditions, mainly Asian, gave him access to other approaches and helped him deepen his spiritual quest, taking him beyond the boundaries of his own tradition. By insisting mostly on experience, on the relation to God beyond words, Merton helped other God-seekers move forward on the path of union with the Divine. Merton can thus be seen as a pioneer in the field of interreligious dialogue, making a significant contribution to the Christian theology of religions.