Quite a while ago, I used this book to figure out what I'd need to do to pay down my mortgage faster than the required time. Then I did it.
The information must be available online now. Even so, I remember how handy it was to be able to flip back and forth in the book when it came to charts and other information. I seem to do better with a physical book when it comes to things like studying a subject. I'm not sure how I would adjust to the digital world of school work these days. Probably not well.