First off great job, it looks like you put a bunch of hard work into this. One area for improvement is the images. Currently some of the more information dense ones are hard to read at small sizes and clicking on them does nothing. Perhaps expand them to full size on a click?
I had to back this out because of a conflict with the filesystem layout and strict epubcheck by itunes. :( Sorry. I did expand the dense image in the introduction to 100% width, which hopefully helps.
