Legal Question in Intellectual Property in Illinois

Probably, but it is not that simple. Someone can use "Spider-Man" to refer to the character if it is necessary for the purpose of description and provided suitable disclaimers are made to avoid infringement of the trademark. See a good Illinois trademark attorney for the proper language and for a review of the book to see if, from a legal standpoint, there is sufficient likelihood of confusion to make a claim for trademark infringement, and to see if the potential defendant is someone you want to tangle with. It's like Marvel probably won't sue Microsoft if they use "Spider-Man" on a book title because MS will do it's homework first and use the term in a way that doesn't infringe, and because even Marvel probably can't afford to go toe to toe with MS as a bluff, because MS will call that bluff. You need to have this reviewed so the CDL (cease and desist letter) is properly worded so it is not likely to end up biting you back should the alleged infringer put up a fight. I am a master at CDLs, and an IL atty, or I can refer to you others who can also write a decent CDL. Don't do it on your own, as CDLs are a gutsy and risky move if self-written, and they can backfire. For instance I recently fended off Superman (DC Comics) over alleged infringement of the trademark KRYPTONITE by my client's KRYPTOTITE tee shirts, and that weakens their KRYPTONITE mark just a little, and certainly more than if they had not written a CDL and found they needed to drop the matter.