__Underlined__ words are links to external resources. When __italicized__ they link internally to other parts of the book. Their text usually indicates where. In the ebook or online, just click them.
You needn’t read the whole book just to get the idea. I present it in layers: immediately in brief, then again at length, in detail, in different aspects.
The book is best read cover to cover. Each section builds upon the last. Every word contributes to understanding, not just numbered chapters but, for example, the blurb and appendices. The instruction lists in the four make chapters are tedious; they can wait till you use them. IKEA-like assembly instructions to come.