Something not immediately clear to me is how to use the book. I see it uses a literate programming format, and it seems very well done. But I don’t see (in the first couple of chapters anyway) any code to show intermediate results. Am I supposed to work through the whole book before getting something that I can see? I’m sure I’m missing something.
It also has an index of all identifiers, which I find quite helpful, and the full source code is available as well.
After you spend some time with the book, how the chapters are laid out make much more sense (at least, that's my experience)