When I was 20 I took a four hour course explaining how to do this. I read hundreds of books this way. Over time I fell out of practice. These techniques work best on paper books because it is easy to jump around and scan. You can take some of these techniques to electronic books.

This is a skill that will not take away your ability to read as you currently do, it is just an available super power when you need it. You can also vary your speed rading based on the content of the book. I have found that I will frequently get more out of a book if I speed read because I am focusing more attention on the task. You can read a book in an hour and still get something out of it or you can take time or speed read certain chapters. When I was in practice I read almost everything this way.

There are some apps that will do this for you and present a stream of words very quickly. I have not tried them yet.

This is how it is done!