Modern textbook design: an architecture for distraction

The design of textbooks in common use at all levels from elementary school through high school are appallingly bad. I’ve come to this conclusion after several years of carefully looking at my sons' books as they went through public middle and high school. What follows is a critique of very common design “features” in these books in reference to visual information design principles. Since I’m not a subject expert in the content of the disciplines presented, I’ll just refer to the visual design, typography and information design principles in general.