This post was published more than a few years ago (on 2008-01-02) and may contain inaccurate technical information, outmoded thoughts, or cringe takes. Proceed at your own risk.
When I ordered a recent After Effects tutorials book, I was offered a Digital Upgrade from Amazon. I took the offer, not looking very closely, but later found that it doesn’t include any of the files that may be on any attached disc(s)— just the scanned pages. Just an FYI.