Make it a rule never to give a child a book you would not read yourself.

This quote means that before you give a book to a child, make sure that it is a book that you would be willing to read yourself. It suggests that adults should not give books to children that they do not enjoy. This is because adults should only give children books that they think will be enjoyable and educational. By reading the book yourself, you can make sure that it is a good choice for the child.