It looks like I'm not the only one who disliked having to carry around a lot of books. Back in the mid-16th century a German publisher created this six books in a book, where you can open it up in different ways to read the different texts.
This particular book is owned by the National Library of Sweden, and it contains religious texts including one by Martin Luther. You can see more images of it from the Flikr page of the National Library of Sweden, but if you want to see it in action, check out Erik Kwakkel's Tumblr! You can also follow him on Twitter @erik_kwakkel