They apprise us about already known facts and concepts.
...They teach things that we don't know also
Books are considered a good source of knowledge. They apprise us about already known facts and concepts. But there are various things for which books do not come very handy.For example, we can't learn swimming by reading it from a book. We have to practice in a pool to get perfect on it. Like swimming, there are many other things which we can only learn by our experiences. And, I think our experiences give us more applicable knowledge than books.
This is your introduction. In that you should not give examples and let body paragraphs to contain them. Here you should introduce the prompt only.
It is good if you include the purpose of your writing (IELTS, TOEFL etc.) in the title so that it helps us align our comments with task related requirments.