From economy to theology, in the constant search for unity between heaven and earth, between the divine and the human. This is the spiritual journey of Sergei Bulgakov, one of the most brilliant thinkers that Russia has never donated to the West, partly because of the political ostracism first, theological then, that his country imposed on him. At the center of his thought is the discovery, during a trip in the Caucasus, of Sophia, the primitive force, the powerful source of the cosmos. "It is neither heaven nor earth: it is the great vault of the sky that arches above the earth. Here there is neither God nor man: in it the divinity itself lives, it is the divine shelter over the world" . For this it is able to combine the apparent extremes, as it is given to see in Christ, in which divine and human nature meet, in which the three-person God shows itself in its identity of Love able to empty itself to give rise to the world, that is the place of his incessant revelation. So the history "is apocalypse [...] through the noise of the events. For every man his life is apocalypse". Sophia becomes the principle of the highest symphony, whose sounds are audible in Sobornost, the union, the agreement, the thinking and living together as brothers with all other men.