This is not an original idea but, when you have thousands of books and you don’t want to use the Dewey decimal system for your home library.  What do you do?

I LIKE IT A LOT!
It has this neat sense of order to it.
FYI
When you see it in person it is rather subtle. 
 You know that it’s organized but it takes a little bit to get what visually is going on.
T comes home with at least a few dozen books a month so now I know what to do with them!
I have room for another thousand or so books in my office, an adjacent room to the library, so I can’t wait to bring this idea into that area.
note:

It never occurred to me until I was almost finished that most books are white or black with colored printing. 

 Red and Blue are indeed political or children’s books mostly.

Multi colored are mostly novels.