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.
A blurb is the book description you find on the back of a book or online to describe a book's contents. Most run several paragraphs, but some publishers want them shorter or in a special format so be sure to check with your publisher's guidelines before you begin work.