what is the importance of the prologue to the text as a whole?

This entire prologue is extremely Communist in its message. Any capitalist society would argue that whoever originally owned the land should get it. Brecht instead argues that whoever can best use the land should get it. It is because of the Communist overtones in the prologue that Brecht originally did not allow the prologue to be printed while he was living in the United States.

The prologue serves yet a third function of allowing Brecht to present his ideas before the play even starts. This is extremely clever of him because the audience receives the moral of the play without even having to watch it. Thus, he gets his Communist message across immediately and only after he has presented the message does he actually allow the play to begin.