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.
An A-Plot is a cinema and television term referring to the plotline that drives the story. This does not necessarily mean it is the most important, but rather the one that forces most of the action. Plot Summary. A plot summary is a brief description of a piece of literature that explains what happens.