2023 Reprint of the 1934 U.S. Edition. Full facsimile of the original edition and not reproduced with Optical Recognition Software. Rufus Matthew Jones was an American religious leader, writer, magazine editor, philosopher, and college professor. One of the most influential Quakers of the 20th century, he was a Quaker historian and theologian as well as a philosopher. The essays of Ralph Waldo Emerson introduced Jones to the idea of George Fox as one of a great historical succession of mystics. This revelation changed Jones's conception of his family's religion. From the writings of the early Quakers, Jones crystallized the concept of the 'inner light," an idea central in particular to modern liberal Quakerism. "The Inner Light is the doctrine that there is something Divine, 'Something of God' in the human soul," he wrote. This inner light was something integral to the human condition, irrespective of a person's religious conviction. He upheld that God is a personal being with whom human beings could interact. He wrote in The Trail of Life in the Middle Years, "The essential characteristic of [mysticism] is the attainment of a personal conviction by an individual that the human spirit and the divine Spirit have met, have found each other, and are in mutual and reciprocal correspondence as spirit with Spirit."