Official Vs Unofficial

  The other day I was thinking about things that are official and things that are unofficial. Why are there unofficial guides to things as in books? I don't really know off hand, but here is what I have to say about it.
  Unofficial guide books as in price guides or guides to a movie or book series are pointless. Why? Well first off they are unlicensed and not the official thing. Another thing is that an unofficial guide my be the only option because the manufacturer of let's say a toy company never put out an official price guide. Why do people make unofficial guides? They make them if they are not authorized by the person who invented what the guide is based on as I mentioned the toy company.
  Official guides on the other hand are usually written by the creator of a movie series for example or someone who is a renowned expert on a particular subject. Toys for example is a particular subject. I do own some unofficial price guides. I own a Batman price guide, and I owned a McDonald's price guide at one point I don't recall if the McDonald's one was official. Official price guides are authorized and or licensed by their respective creators and or copyright holders whereas an unofficial one is not. I don't get how unofficial ones don't get sued over the fact that they are not authorized to do so. Why don't they go the extra mile and get it authorized? It's baffling how authors of unauthorized guides are so lazy to do so.
  On the other hand Unofficial price guides can be just as useful as an official one is. Sometimes they can be better than the official one. But unofficial guides lack the luster as the official version does. You get that bootleg feeling when you read it, knowing it comes from a fan not an expert.