Just because we're not told about such things does not mean that they don't exist. Or do you give information like that about yourself when you write your blog?!
(The last sentence does not apply if your nick is 'burrahobbit'...)
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'Mercy!' cried Gandalf. 'If the giving of information is to be the cure of your inquisitiveness, I shall spend all the rest of my days in answering you. What more do you want to know?' 'The whole history of Middle-earth..
.'