There are some very important features of books that distinguish them from other sources of information:
Comprehensiveness: academic books typically cover their subject matter both broadly and in considerable detail. They afford the reader an overview of the topic, details of its many facets, and often a history of the subject.
Reliability: books are usually subjected to a lengthy review process that includes lots of fact checking and revisions
Uniqueness: much of the information published in books is only available in books .
"Without books, history is silent, literature dumb, science crippled, thought and speculation at a standstill. Without books, the development of civilization would have been impossible. They are engines of change.... They are companions, teachers, magicians, bankers of the treasures of the mind. Books are humanity in print."
Barbara Tuchman, Historian
Coming of age in Samoa
Oral Literature and Moral Education among the Lakeside Tonga of Northern Malawi by 
Social Structure, Space and Possession in Tongan Culture and Language by 
