Scholars have discovered a way to peer through the spines of books printed during the Renaissance and gain access to the medieval writings that often lurk beneath.

Nowadays, medieval manuscripts are highly valued, but during the early Renaissance, many were regarded as little more than scrap paper, notes The Guardian.
Once the printed book appeared, hand-written volumes fell from fashion, and their pages were cut up and used to reinforce the spines of new publications.
Scholars have known about these hidden treasures for some time, but not having a way to get to them without destroying books has stood in the way of their study. 
Not long ago, Leiden University book historian Erik Kwakkel became curious about the possibility of using new developments to help solve the old book problems. 
He contacted a colleague at Delft University of Technology and suggested the two try to take a look through the book spines using macro X-ray fluorescence spectrometry, notes Smithsonian.com.
According to The Guardian, the endeavor was a resounding success, and the hidden passages were not only viewable but clear enough to read. 
At this time, a large-scale exploration of what lurks beneath the covers isn’t feasible due to the length of time the scans take.
However, the researchers are hopeful technology will march on, and future developments will speed the process.