One of the axioms of Trademark law is that you cannot trademark the title of a work. There are some obvious exceptions: Harry Potter designates a series, not the title of a single work. Rocky also designates the source of a series of movies with similar names – but by and large you cannot trademark the title of a single work.
This is because trademarks are supposed to answer the question “Where am I from?” not “What am I?”
“Harry Potter” is an answer to “Where am I from?” While “the Goblet of Fire” answers the latter question.
If you’re releasing a book, and you’d like to trademark the book name, consider using that trademark to identify other goods and services you offer. For example, if you want to publish a book called Modern Renaissance Legal, consider launching a firm with the same name, offering legal services at the same time. This helps broaden and strengthen your brand, as well as serving as a stronger basis for registration of your trademark.