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.