Sadly, this small book does not do justice to the depth of InDesign. Here are a few other things I use all the time. To learn more about these, check the resources listed on the opposite page.
Paragraph Rules: I love paragraph rules. They are lines/strokes that you can attach to text. Every heading in this book that has a dotted line beneath it is using a paragraph rule; it is built into that style sheet so I just type and the dotted line appears. In fact, paragraph rules are dividing each of the paragraphs on this page (and nested styles that format the words in front of the colons automatically).
More on the Pen tool: The Pen tool is amazingly useful and it would be worth your time to learn it well.
Layers: InDesign has ...