In the ancient spiritual traditions of the Eastern Church, with the holy Mount Athos at its center, wonderful spiritual treasures are hidden. In this spiritual realm, devotion and love have always been at the forefront, while rational theology took a back seat. Therefore, it is not surprising that the prayer of the heart was born in this environment. Johannes Clausner describes in his soul guide the roots, historical tradition, and practice of the prayer of the heart. The focus is always on access to one's own inner self. The prayer of the heart is a unique path into the depths of one's own soul, which can also be wonderfully combined with other practices. It expands one's inner life and opens up new sources of life energy.