The PDF still doesn't help much. The expositionary style of breaking out inner code blocks from their call site harms the ability to understand what's happening. It's nearly impossible to follow in the raw source. Hyperlinks don't improve matters much and the PDF rendering doesn't have rational layout for details like numeric tables.
That said, have a gander here: http://brokestream.com/tex.pdf
Not nearly as good as the hardcover, which has a proper table of contents and index.
The key is to imagine 40 years of progress along these lines. I can't imagine our default target would be paper.