I thoroughly enjoyed the sample chapter. Liked the illustrations, which made the points very clear. And the humor is welcome.
Just one English language style suggestion: Consider reducing the number of expressions of "the fact that" in the text. The occasional "the fact that" is fine. But speaking for myself, it can become irritating and unnecessary when it's frequent.
I'd like to also say that I enjoyed the discussion on the Scala Types podcast where Derek discussed (among other things) Agents. I'm looking forward to the chapter on Agents when the book comes out.