Propound why a library is said to be the memory of the human race?

Yes, a library is said to the memory of the human race because it is the place where thousands and thousands of books are placed. In these books, literally many centuries are hidden.  There is no topic in the world which is not being covered by the researchers, authors, writers, scientists etc. We can find the books from the history of mankind to the coming eras of the world. The authors who wrote the books may have died several years ago, but their books are still read by millions of people. There descriptions, illustrations, thoughts, story telling, etc are present as a memory. So it won't be wrong if we say that library is memory of the human race.

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