What is the theme in Brecht on Theatre: The Development of an Aesthetic by Bertolt Brecht?

The relationship between theatre and social change is at the heart of this book. Brecht's personal and artistic philosophies were entirely intertwined - the personal agenda / impulse was the artistic agenda / impulse, and vice versa. At the core of each of these beliefs was Marxism/Socialism. For Brecht, the personal and artistic goal was power and wisdom for the people, equality (economic, social, political) for all, and the overthrow of what he and like-minded socialists believed to be the elitist social and power structure of the time. In other words, he believed in the power and necessity of transformation, advocated for it, and saw his work as a theatre artist as a necessary component of that transformation.