The Categorical Imperative is supposed to provide a way for us to evaluate moral actions and to make moral judgments. It is not a command to perform specific actions -- it does not say, follow the 10 commandments, or respect your elders.
A blurb on a book can be any combination of quotes from the work, the author, the publisher, reviewers or fans, a summary of the plot, a biography of the author or simply claims about the importance of the work.
Imagine that you're writing a jacket blurb for the novel, one that will pique the casual browser's curiosity and make him or her want to buy the book to see what happens. Read a few jacket blurbs, to get a feel for how it's done. You've just seen a terrific movie. You're describing it to your friend.