I'm coming across lots of great quotes, but I found this one particularly arresting:
When one of the best judges of drama said that the more original playwrights of the twenties "start completely fresh," he listed only antirealists. The antirealists always get all the credit for originality. Actually the realists were just as much in revolt. In a sense they were twice as much in revolt, since they rejected not only the antirealistic styles--such as expressionism--but the established naturalistic styles of the nineties. They wanted to be more naturalistic still.
In this essay, "From Strindberg to Brecht," Bentley is positioning Brecht as a kind of realist, with his Epic theater standing athwart expressionism. What's stunning to me about this quote, too, is how relevant these debates still seem to us now (and how we're already looking back on our own "nineties," and will before long face our very own "twenties").