User blog comment:Gravityfan1931/the writer of the books/@comment-7527615-20140811192433

This is theory has to be correct! It is 99% possible that the author of the books is, infact, Old Man Mcguket (1% is someone else). I have a theory on why he turned insane though. Look, we all know Bill Cipher is a Dream Demon (right?) Well, maybe Bill went inside Old Man Mcguket's head, and did something in it that made him insane. :3