On the one hand, books hold all knowledge gained by previous generations. Basically, people inherited this holder of humankind’s experience. This source of knowledge usually can not be changed, in particular history books that were written on real events and real people. For example, we can assess to information about 2nd World War just by use of books, not our experiences. Moreover, before make new discoveries in certain science, people have to acquire fundamental knowledge about the previous achievements from books. Thus, we can not create the Television without basic knowledge on Micro electric.
On the other hand, I think that “the truth comes from practice and experience”. The knowledge from experience helps us as much as those from books. For instance, at old times people thought that Earth was flat, but it was concluded from observations and measurement that we are living on a global planet. There are a lot new inventions and new products which could not be found from textbooks. Our society and world are developed through continuous practices, those knowledge, never found in books, such as internet, e-business etc. are all developed through new practices.
In conclusion, I might say that people are continually assessing the creditability of the knowledge written in books and discovering new things by experiences. Both of these sources are important, and it is essential to know how to combine them