Some chapters begin with a very standard "what you should learn in this chapter" section. Other chapters lack this. We really should strive to make that consistent across all chapters.

There are a number of terms about which we assume previous knowledge. One simple option is to hyperlink to good explanations of these terms externally; but a better solution might be to link to a glossary at the end of the text. We're starting to collect these in our Glossary of Terms.