The document you're about to enter does not have a linear order. It consists of teaching notes, and its organization can be likened to that of a mobile. While there are discrete points of entry, within each section some concepts are larger and weightier than others. Some are hierarchically greater, and some reside at a greater distance to some than they do to others. While paragraphs under a heading are arranged vertically, remember that there is also a horizontal and spatial dimension--so use the hyperlinks to jump around.
These thoughts come from many great minds and have contriubted to my thinking on these subjects. If you'd like to pursue these thoughts, let me know, and I'll give you the author and work. Individual paragraphs are often distillations of powerful insights. Consider the following paragraph:
One of the most powerful ideas on the planet
was the realization that it was possible to
observe nature and learn from it and apply that
knowledge to our daily life. That paragraph
brackets a number of paradigm-shifting observations humans have made. The
law of gravity is covered by it, and so is one of the most powerful,
life-altering activities human beings ever embarked on--the creation of
agriculture. In short, while it's appropriate to dip in and out, to read
in one section and then in another, do read slowly and thoughtfully. The
time spent will be repaid many times. Enjoy!