I was reminded of Martin Buber's "I and Thou" last week when I was visiting the National Civil Rights Museum in Memphis. ("I and Thou" was originally called "Ich und Du", published in 1923, modern translation here )
Martin Luther King, Jr references Buber in his Letter From Birmingham Jail, written April 16, 1963: "Segregation, to use the terminology of the Jewish philosopher Martin Buber, substitutes an "I-it" relationship for an "I-thou" relationship and ends up relegating persons to the status of things."
Buber's "I-it" relationship is a subject-to-object relationship in which two people are separate. The "I-thou" relationship is a subject-to-subject relationship where two human beings are aware of their unity of being, there is connection instead of separation.