A codex is a fancy name for a book made out of paper or parchment that is folded together like a sandwich and has a cover on the outside to protect it. It's like the book you might read at bedtime or in class, but it’s made in a different way. Back in ancient times, they didn't have printing presses or computers, so they had to write everything by hand. A codex was a way to organize all the handwritten pages into a book so people could easily find the information they were looking for. It was kind of like a big puzzle, where all the pieces fit together in just the right way. Today, we still use codices to store information, like in libraries or museums where they keep old books safe for people to read and learn from. So the next time you pick up a book, just remember it's actually a really cool codex!