In page 37 under Separating your concerns, we see a model with each layer recommended to separate an application for scalability.

Yet on the following chapter 4 page 69, Scott decides to include the UX layer with the presentation layer?

What's the benefit of each? What is the best practice?

Also I notice in page 52(Ch3) in the UX layer he is utilizing delegation and Interfaces yet again in Chapter 4 he bypasses this altogether??? What gives???