On what only did not write their thoughts ancient people, till there was a regular book! First, cut out the symbols on the stone, then the tree bark, then there were scrolls. Although the most convenient is book.
Reliable cover kept the sequence of sheets, a thick cover protected the pages from folding. Meanwhile, books are different. And it's not in the size or number of sheets. It goes on the cover. As it turned out, the same book can be read six ways. A vivid example — a small volume which was printed in 16th century Germany.
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Incredible book attached metal clips, revealing that, you can read a particular publication. This kind of binding is called "dos-a-dos", from the French "back to back" and today it is almost no use.
First reported on the original edition of the famous historian Erik Kwakkel, who have long been engaged in the study of medieval books. Employee of Leiden University (the Netherlands) was shocked by the uniqueness of the publication. Usually the method of "dos-a-dos" United together 2 books. Here in one publication, the creators have managed to collect 6 different books, United by religious themes.