“During the burdensome hours of life, on days when you find yourself sad and despondent, open this book! With echoes of voices from above, it will give you courage; it will inspire you to be patient, to submit to the eternal laws!” – Thus states Léon Denis in the Introduction to the present work. The purpose of human existence and the law of destiny are the central themes of The Great Enigma, which reveals to us a God of justice, but also of infinite love. The work is structured in 3 parts: - The first part makes an analysis of the Universe in its harmonious and unified activity, relating physical phenomena to a greater power that is responsible for that balance: God;- The second part studies the elements of nature such as: the sky, the forest, the oceans and the mountains, striving to unveil the secret of eternal life via the history of the formation of the worlds; - The third part discusses the circular law, which “...presides over all the movements of the world,” explaining that “Each being gravitates in a circle; each life traces a circuit; all human history may be divided into cycles.”