Okay, last thing first. Not all artist paint that way. Many oscillate betweeen fine and broad detail. They are usually taught broad to fine, so that scale and proportion are captured porperly, since focusing on detail too early "can" but isn't necessarily fatal.
Going to the first question, I first thought "oh yeah whole to part again". Then I the "treat each chapter as a book" idea kind of messes that up.
Now, I know AlexK and many others have more experience than I but I thought back to the material I've learned in the past. Sometimes as you learn the question, you start to think of the big questions. These a questions you wouldn't have thought of until you had enough detailed knowledge.
Other areas, I thing that broad to fine is natural. Also for technical material, which is often poorly presented, PWMS is ideal for getting the whole picture. Computer technical material very often dwells on the detail, which is perhaps why some think they need to memorize everything. Information is easiest to remember when it is acquired in context, namely broad to fine. Oooops I'm rambling.
So I think that even though we are told to treat each chapter as a book. I would recommend PRing the whole book, and work on the activating a chapter at a time. However, I suspect that it would be good to try and do the big picture / big question on the whole book. The sooner you have a framework, the sooner you will have something to attach those ideas too. Ummmm I guess that's learning and not just reading.... but then don't I hear that "accelerated learning" phrase around here. 
