I purchased this book and haven't yet seen the print version, but I can tell you that the supposed "upgrade" to a digital version is unreadable. The page images are fuzzy so that the text is illegible in some instances. For a book where it's really important to see the details, this is unacceptable. I've asked Amazon for a refund and I won't be ordering any more "upgrades."So this review isn't about the substance of the book (I'll know more about that when I get the paper copy). It's about the production of the digital version.