Some of the most interesting books were especially challenging. One in old German that was missing a couple of pages. It was a popular fairytale so I found the missing content online and a closely matching font, and reconstructed the pages. Another was in an Asian script I not only couldn't read, I didn't know how to sort or even properly rotate some loose pages, so I had to ask the owner. In a few cases when bits of the cover were missing, I found photos online, and printed a patch. Fun times!