You are confusing two separate concepts: trademark and copyright. I'll give you a broad overview of both of these, although the details will differ depending on what country's law we're talking about.
A copyright is held by the creator of a work of artistic expression. It gives the creator certain exclusive rights, including the right to create copies of the work and to prepare derivative works.
For example: The movie "Star Wars" is a work of artistic expression. You cannot copy "Star Wars," or any significant part of it--including the script, the music, etc.--without the permission of the copyright owner, unless your use fits into one of the exceptions to copyright in your jurisdiction.
Likewise, you cannot write your own book featuring the Star Wars characters: that would be a derivative work, a work based on the original work, and would violate the rights of the copyright holder.
Without having read the book in question, I'm not going to comment on whether it does or doesn't infringe the film's copyright. But ideas can't be copyrighted. A film review, for instance, isn't a copyright violation--and a longer work discussing the ideas involved in a film isn't necessarily a copyright violation, either. Copyright only protects the expression itself--the language, the images. You are very limited in how much of that you can copy, but as long as you're using your own words, copyright protection is less of a concern.
Trademarks, on the other hand, are intended to protect a business from customer confusion. Trademarks are not protected in the same way as copyrights; the key analysis of a trademark infringement lawsuit is: does it create confusion about the origin of the goods? For example: if you slap a swoosh on a shoe, Nike will sue you. If you use a swoosh in a political cartoon criticizing Nike, they won't, because nobody is going to think Nike wrote the political cartoon.
So: If you write a book and call it: "Ewoks Gone Wild: A Star Wars Story," Disney will sue you, because it would be reasonable for someone who saw that book in a store to think that Disney authorized that book. If you wrote a book called "Forcing the Issue: The Hermeneutics of Science Fiction Movies from Star Wars to Inception", the case would be less clear-cut.
But the important thing to understand is that these issues are complicated. There are exceptions to these rules; there are applications that may not be obvious to the non-lawyer ("initial interest confusion" is one minefield in U.S. trademark law), there are national and EU-specific considerations, there are safe harbors, and there are practical considerations, like whether you can afford to fight a lawsuit even if you're in the right.
Therefore, I'm not going to tell you whether your hypothetical work would infringe anyone's copyright or trademark, and I'm not going to give you a set of rules on how to avoid it. The only person you should be listening to that sort of advice from is a real, non-anonymous-internet lawyer, licensed to practice in your jurisdiction, who is familiar with the specific details of your specific situation.