How to mark a book ( Mortimer Adler)

 So far this was the least interesting story or essay I've read. It was difficult to read because it was so long and I wasn't necessarily interested in the topic. The author spoke about the different ways of marking in a book such as underlining, drawing vertical lines in the margins or highlighting words. I think if the topic was focused more on drawing or painting I'd be much more interested and if it wasn't so long.