Martin Buber's I and Thou argues that humans engage with the world in two ways.
One is with the attitude of an `I' towards an `It', where the self stands apart from objects as items of experience or use.
The other is with the attitude of an `I' towards a `Thou', where the self enters into real relation with other people, or nature, or God.
Addressing modern technological society, Buber claims that while the `I-It' attitude is necessary for existence, human life finds its meaning in personal relationships of the `I-Thou' sort.
I and Thou is Buber's masterpiece, the basis of his religious philosophy of dialogue, and among the most influential studies of the human condition in the 20th century.