There's nothing sacred about taking in information as a stream of images brought in through the eyes. It happens to be the way we read; but we also hear and feel and smell, and all of these teach us something...and all have the power to bring back sudden memories. We can replace written books by books that we experience in all these ways.
Or maybe we will replace books with information environments that we experience directly in the brain. This is a question of technology, science, and medicine for the interconnections between our Information Repository (external) and our Information Repository (internal: the brain's memory system). There must be a physical link, and an encoding system that our brains can interpret.
At the basic level, books are the interconnection between the information system and our brains. The encodings we use today are the encryption of data into words and letters and pictures through language and images. Our internal decoding systems interpret images and recast letter strings into words that we can map onto the words we use in speech to get at the meanings we use when we speak them. (And words have their own internal encodings, which we can't generally perceive, and don't generally need to).
I think it will be a glorious day when I can plug directly in to the data bank and download the information I need. It think this will be the case. I'm not really sure about it yet.
I'd like to rest my eyes for a bit, though.