Social Media has taken over as a method for getting noticed. How can you limit who sees you or is that a dumb idea?
If you are marketing you books, why would you want to limit who sees you unless you are thinking about your personal profile rather than your public figure profile.
Facebook makes it easy to have privacy settings on your personal page. You can limit what the world sees and what you share. Even with privacy settings, your friends could share your information without you knowing about it. Although this may work in the short term, just remember that whatever you post stays almost forever, so post only items that build your reputation and don’t damage it.