Starting from a radical phenomenology of life, this book does not ask whether Christianity is true or false, but rather what kind of truth it proposes to think and offers to humanity for their salvation. Since man does not emerge from the world but is begotten in the life of God, he is its "Son." This life of God is simultaneously the self-revelation of life as the essence of God, so that man as "Living" must ultimately be understood from this self-revelation, namely as "Son" in the transcendental "Ur-Son," in Christ. A phenomenology of Christ shows more precisely how he is begotten as the eternal, self-affective "Word" of the "Father," in order to form the concrete access of each "I" to life in his original ipseity as "First-Living." This birth of "man" as "Son in the Son" not only reverses all given conceptions.