The author says we shouldn't keep books, we should assimilate books into our model of the world, and then dispense with the book. To an approximation, I agree. I also agree with the idea that sometimes collecting books and bookmarks can lead to a false sense of satiety with our intellectual progress.

I disagree with his point that notes actually do represent assimilated information in a way that the books themselves don't. Notes might guarantee a certain level of assimilation, but they don't qualify as "knowledge" in the way the author maintains. There's other good reasons to keep notes, but not because they're more a part of your knowledge base than the book itself.