The Lion and the Mouse: The battle that reshaped children’s literature.
"Between 1881 and 1917, Andrew Carnegie underwrote the construction of more than sixteen hundred public libraries in the United States, buildings from which children were routinely turned away, because they needed to be protected from morally corrupting books, especially novels."
From the New Yorker, a short history of kids and books. I remember being judged by the librarian before I received my first library card: the rules were that you had to spend time in the children's area so that the librarian could see how you behaved around the books. If you could be quiet and treat the books with respect, she would grant you the privilege of borrowing. I remember meeting her with my mother and being introduced and told about what library books were and how they had to be kept in good condition for others to borrow. It was a pretty formal introduction to the borrowing process.