Nepal contains part of the Himalayas, the highest mountain range in the world. Eight of the fourteen eight-thousanders are located in the country, either in whole or shared across a border with China or India.
It is a battle without a victor, with pages named as the reward: a book is argued over, named either brilliance or fiend. You are certain it is unworthy, appalled by its simpering text and sentimentality. It is little more than a glorified romance, you say. It cannot be considered good. It must instead be criticized, exposed for all of its faults – of which there are many. Your friend and sparring partner, however, believes you to be wrong. A book is considered perfect, praised for its themes and techniques. Your opinion, it is sworn, is without merit. Your critiques are poorly formed.
Such debates are common within the world of literature; with individuals unable to reach a consensus over texts and their importance. You prefer one story. Your friend prefers another. And the result is constant bickering.
And that bickering was what formed the notion of literary criticism so long ago.
Literary criticism, in its most modern definition, is the study of the written word, with a purpose to evaluate and understand it. It is not the same as its often confused counterpart of literary theory; which seeks to learn through philosophy and abstraction. This is instead meant to be an application of logic. Books are to be mastered through reasoning.
But that mastery is unable to be clearly secured. Opinions vary over what must be evaluated in stories, what the common expectations should be. During the 5th century, Aristotle declared that poetry was a lesser form than prose and that all epics must follow their established structures to be considered valid. That idea does not persist now, however. There is a leniency toward themes and genres, with critics accepting new ideas. Those ideas, though, have divided all on how to rank them.
Literary criticism can therefore only be defined to the individual. It is a search for merit, rather than metaphor, and seeks to dissect technique. Books are to be judged time and time again.
There are no rules. There are simply preferences.