Congratulations on writing a book and getting it out in the world.

1. It took me two tries to realize there is more than the table of contents and find the Unlabeled links on the left. Just make the text in the TOC clickable.

2. Maybe text navigation didn't work the first time because I did not select the correct option on the popup about interaction. This is a distraction from reading irrespective of what I picked.

3. Advice: make the reading experience work like readers expect. There are conventions. Trying to be clever doesn't benefit your readers...and will annoy at least one of them.

4. Nobody likes popups. Nobody. Nobody.

Good luck.