A(n) hypertext document such as this gives you a lot of freedom to jump around. Having jumped, however, it can be hard to get back where you were. So, I’m putting at the bottom of each page a “Contents” link back here. Your browser, of course, probably lets you back up freely through the pages you’ve recently visited.
You can look at the story I’m telling, moreover, from a number of angles.* Any imaginable “Table of Contents” would serve some points of view better than others. So, I’m providing several summaries and contextual aids as the associated issues come up, as well as my usual Page Index.