The human back is the large posterior area of the human body, rising from the top of the buttocks to the back of the neck and the shoulders. It is the surface opposite to the chest, its height being defined by the vertebral column (commonly referred to as the spine or backbone) and its breadth being supported by the ribcage and shoulders. The spinal canal runs through the spine and provides nerves to the rest of the body.

The central feature of the human back is the vertebral column, specifically the length from the top of the thoracic vertebrae to the bottom of the lumbar vertebrae, which houses the spinal cord in its spinal canal, and which generally has some curvature that gives shape to the back. The ribcage extends from the spine at the top of the back (with the top of the ribcage corresponding to the T1 vertebra), more than halfway down the length of the back, leaving an area with less protection between the bottom of the ribcage and the hips. The width of the back at the top is defined by the scapula, the broad, flat bones of the shoulders.

Dialogue (sometimes spelled dialog in American English) is a literary and theatrical form consisting of a written or spoken conversational exchange between two or more ("dia" means through or across) people. Its chief historical origins as narrative, philosophical or didactic device are to be found in classical Greek and Indian literature, in particular in the ancient art of rhetoric.

While the dialogue was less important in the ninetenth cnetury than it had been in the eighteenth, it was not extinct. The British author W.H. Mallock employed it successfully in his work "The New Republic," which was explicitly based on Plato's "Republic" and on the writings of Thomas Love Peacock. But the notion of dialogue reemerged in the cultural mainstream in the work of cultural critics such as Mikhail Bakhtin and Paulo Freire, theologians such as Martin Buber, as an existential palliative to counter atomization and social alienation in mass industrial society.

Dialogue as a genre in the Middle East and Asia dates back to the year 1433 in Japan, Sumerian disputations preserved in copies from the late third millennium BC and to Rigvedic dialogue hymns and to the Mahabharata.