This is a dos-à-dos book, which means it’s a single book with a hard back, which forms the cover for another book. However, what’s special about this one is that it contains not just two books… but actually has 4 others hidden! Each book opens differently with a little clasp. This book was created in Germany and contains religious devotional texts. This rare, intricately designed book is at the National Library of Sweden. It’s like a Medieval version of Amazon’s Kindle!
Now that’s what I call bathroom reading material. This thing is amazing! If you think this is interesting, you should check out [Erik Kwakkel](http://erikkwakkel.tumblr.com/). He’s a book historian at Leiden University in the Netherlands, and is the one responsible for bringing stories like this to us.