For thousands of years, paper has been a precious commodity, so it has often been reused. Even when the Bronte sisters were writing, paper was so expensive that siblings Anne, Charlotte, Emily and Branwell would routinely cut up magazines and sew up bindings by hand to create small books (which they filled with miniature print). As author Deborah Lutz details in her book "The Bronte Cabinet," unused blank paper was an extravagance, even for middle-class children.

Those who produced books were also looking for ways to conserve pricey paper: Bindings for new books made between the 15th and 18th centuries were routinely made from cut up pieces of handwritten tomes from the Middle Ages. After all, the older writings wouldn't be seen. Considered out-of-date once the modern printing press was invented, the handwritten books' secrets were tucked inside the bindings of around one-fifth of the books from the time period. Dr. Erik Kwakkel, a medieval book historian at Leiden University, describes these hidden pages from up to 1,300 years ago as “stowaways from a distant past."

While experts knew some of these lost manuscripts were hidden inside books, there was no way to access the information they held without tearing the books apart — until now. Using macro X-ray fluorescence spectrometry, interior pages can be read without even touching the binding of a book.

Fascinatingly, this technique comes via professor Joris Dik at the Delft University of Technology in Holland, who originally developed the technology to scan old master paintings. In 2011, he was rewarded for his work when he found a Rembrandt self-portrait hidden beneath another painting (see video below).

“A thin beam of X-rays is used to scan the object, charting the presence and abundance of various elements below the surface. That is how iron, copper and zinc, the main element constituents of medieval inks, could be viewed, even when covered by a layer of paper or parchment,” Dik told the Guardian.

So far, the scans (which take some time to do, and faster methods are being researched) have revealed one important find in the old books: a piece of a 12th-century manuscript that includes excerpts from the work of the monk Bede, who is also called “the Father of English history.” But researchers are looking for so much more.

"It would be great to find a fragment of a very old copy of a Bible, the most important text in the Middle Ages. Every library has thousands of these bindings, especially the larger collections. If you go to the British Library or the Bodleian [in Oxford], they will have thousands of these bindings. So you can see how that adds up to a huge potential,” says Kwakkel.

Whatever is found in these texts, it's every book-lovers dream to find other stories hidden within dusty volumes; now it seems that dream is a reality.

Starre Vartan ( @ecochickie ) covers conscious consumption, health and science as she travels the world exploring new cultures and ideas.

Ancient books may hide other texts inside
Experts think that 1/5 of all old books contain hidden pages, and modern X-ray technology may help them find the secret text.