Yes a library is said to be the memory of the human race. It is because of the fact that library is the only place where thousands and thousands of books are placed from the beginning of the world to the prediction of the ending of the world, from cultures to heritages, from personalities to places of the world, from arts to science, from fiction to truth and so on. There is literally no subject or area of the world which is not covered in the books. People who wrote the books might have passed away years ago, but their writings are still alive as a memory in the library. So that is why a library is called the Memory of the Human Race