Not every book is right for every child.
Children mature at different rates.
They have different interests, reading abilities and life experiences. Librarians, while glad to share their expertise, believe that decisions about what materials are suitable for particular children should be made by the people who know them best their parents or guardians. They are generally not attracted to materials that are too advanced for their reading or maturity levels. Provide clear guidelines for your children. Let them know there are subjects or areas that you prefer be off limits and explain why.