I wonder does the typical reader know how much effort goes into producing a finished book? I've never written one. I have written documents with professional writers, I've seen a glimpse of the effort they put into the work.

Just saw this new TDD in Swift book by Gio Lodi. Thinking about downloading the Kindel version.

Speaking of books... did you ever see Push Pop Press - Our Choice - by Al Gore. The version for the iPad was a new media concept. Which seemed to cross Steve Jobs by using the intellectual property of Apple and was bought by Facebook. The tech in the book was well before it's time. It might be showing up again in How to Say Cheese, the format of the book, chapters and page display looks the same. Wonder if the underlying code is open-sourced?

Think what one could do with that rich text media and programming books...

One of the best uses of rich images I've seen in books is by Big Mountain Studios.