That turning is nothing less than one's redemption in God, the "eternal" Absolute Person.  
The author concludes one of its chapters by explaining that the titular concept "does not help to sustain you in life, it only helps you to glimpse eternity."  It goes on to explain that through relationships individuals can turn their being towards the center of reality and "approach the Face."  That turning is nothing less than one's redemption in God, the "eternal" Absolute Person.  It begins by describing the two types of relationships that humans enter, and then indicates the two-fold attitude that humans possess toward the world as indicated by the two title words.  FTP, name this seminal 1923 philosophical work by Martin Buber.
The author concludes one of its chapters by explaining that the titular concept "does not help to sustain you in life, it only helps you to glimpse eternity."  
I and Thou or Ich und Du