Reddit reviews Demanding the Impossible

The absolute easiest of his books is Demanding the Impossible. It is an extended interview, so it broken up into relatively concise and self-contained sections for each question.

If you're looking for full book that's still on the easy side, I would check out Trouble in Paradise or First as Tragedy, Then as Farce, which are on similar topics. His book Violence is also quite readable, but I think the other three make better introductions to his thought.