Read Knowing Yourself - A Medieval Romance Page 35
Medieval Literacy
It's easy for some to believe that everyone in Medieval times was illiterate and uneducated. Especially in a modern world where current statistics are that 99.99% of people in the United States are functionally literate. While the Medieval times certainly did not reach our modern 99.99% level, it also wasn't populated solely by people who had no idea what letters were.
First, let's talk about books. A literate person needed something to read. Bound printed books, as we know them today, didn't exist back then. Remember, the printing press wasn't created by Gutenberg until around 1440. Before then, books were created by hand by copying an existing book. Entire monasteries dedicated their attention to hand-copying books page after page. Many of these books were Holy books such as the Bible. Because the creation of a book was so time-intensive, the resulting book was extremely expensive. Typically only the most wealthy of people would have a book.
While in Roman times people would read from scrolls of parchment, by the Middle Ages a standard form was the "codex" - a series of pages connected at the back / spine. In essence a codex is the shape of our current books - just the pages were written out by hand. The use of paper (wood pulp) began to replace parchment (animal skin) - paper was cheaper and this also helped books become a bit more accessible.
Because paper and parchment were relatively expensive, people would never use those for note taking. Instead, they would use wax tablets. Wax tablets have been used since nearly the beginning of civilization and were even used as recently as the 1800s. They have been a standard method of note taking for many different civilizations. The benefit of a wax tablet was that wax was easy to get, you could write whatever you wished with a stylus, and then simply mush the wax down when you were done to start afresh. You could write words, numbers, draw shapes, whatever you wished. Here's a great article all about how heavily the wax tablet was used in medieval times –