You are. Most of our history has been preserved in books that were inaccessible to almost everybody and that nobody opened for hundreds of years. The important thing is that things are preserved somewhere, even if to read them you need a fully equipped laboratory and boffins in white gowns. That's how we read our most ancient documents anyway. Once the information has been retrieved and copied, it's safe.
I think you are confusing history with archeology. They are obviously related, but they are not the same thing. Preserving history requires keeping it alive. Those books you speak about were endlessly copied and read. I am willing to bet that most of you know about history you have learned from articles or books of people who read other books, and so on. Archeology steps in when history ends up as a CD-in-a-box or tablet-in-a-tomb. And even then we often loose context and meaning.
