Oh yes, Andrea! And also his work with Hans Eisler, the composer of the national anthem of the DDR. Though I do find his work as a director the most fascinating... many things that we take for granted in the theatre today-- the "alienation effect", breaking the Fourth Wall, and the projections and signs, among many others, were truly ahead of their time.
This, from Solidarity Song, which was set to music by the Jefferson Airplane's Marty Balin many years later:
"Forward, without forgetting
Till the concrete question is hurled
When starving or when eating:
Whose tomorrow is tomorrow?
And whose world is the world?"
Whose indeed?
And this, from "From A German War Primer":
"Amongst the highly placed
It is considered low to talk about food.
The fact is: they have
Already eaten."