The Forest of Stone Steles Museum, or the Beilin Museum, is more or less an ancient Chinese library. You see, even though the Chinese did invent the mixing together of fibers of cellulose (aka paper), it's not quite the safest way for keeping information. So for something super important, like a set of rules or poems written by the greatest minds of their time, you want something more fire and water proof. Learning (not really) from the ancient rules of the Japanese じゃんけんぽん, the stone was elected.
The steles found here are divided in seven rooms, each one containing scripture from different dynasties of China. The first room, for example, has a group of tablets with 12 reading books inscribed. Another reason, beside preservation, was to prevent errors in copy. Because some Chinese characters are complicated and one little stroke makes a difference, it would not be unusual to see mistakes in handwritten copies.