Actually... I and several others here and elsewhere have made the statement that we think that Games Workshop was attempting to use Trademarks in a way to control books. This is tantamount to the same thing as trying to Trademark a book. Either they are ignorant of the law (which I doubt) or they were attempting to game the system and inappropriately use their weight to get their way.
Except, they didn't take legal action. They still haven't. Why is that? They did, in fact, go out of their way in their press release to backpedal like hell saying the opposite of what they sent to Amazon that got the book pulled in the first place. More to the point, why this particular author? Why didn't Games Workshop go after a big fish if they MUST defend their IP? If what you say is true, we should now see the formal case launched in the legal arena. Their threat, after all, to Amazon indicates that is what we would see if it wasn't pulled. When do you expect the case to be filed?The action GW are taking is with unlicenced use of their registered mark of trade (or registered trademark if you prefer) under the specific term "Space Marine". This is Space Marine with captials used as a proper noun, rather than space marine used as adjective noun. GW are entitled to challenge any use of any of their registered marks of trade that are unlicenced. Any and all unlicenced use of their registered mark could lead to a dilution of the brand and an undermining of their value.
If you expect that you would be wrong. You can, indeed, release a book of that name. I don't even think the company that owns Scotch Tape would ask you either, even if they had a Trademark. This has been covered many times now, but it bears repeating; TRADEMARK doesn't apply to works of art and fiction in the way you are suggesting. You cannot Trademark ideas. You can only Trademark a particular image/look/presentation for an identifiable product. Hence, the words "Star Wars" presented in a specific LOGO can be Trademarked, but the words cannot.Your example is quite right but in this case irrelevant. If I were to release a book with the term "Scotch Tape" whether it was about the sticky tape or a murder mystery set in the highlands where the only evidence is in the form of a tape I would expect to be asked to change the name so as to not cause confusion with the "popular" brand of sticky tape. Indeed this is quite a weak argument in this case as I doubt the Scotch Tape is a registered trademark when it comes to written works.