Although both Mark Twain and James Cooper are both respectable authors, Mark Twain calls out James Cooper. In Twain's "Fenimore Cooper's Literary Offenses," one may assert several purposes as to why Twain would want to confront issues concerning Cooper's literary style and effectiveness. Consequently, one may also say that Twain does not fairly represent the novels of Cooper, such as "The Deerslayer." As Twain was a realist in his literary works, Cooper is best described as a Romanticist. Thus, Twain viewed Cooper's Romantic style of writing as unfavorable to any reader. One may begin to realize that Twain did not want to be the only person who did not approve of Cooper's novels.
Twain wants to shift focus from Cooper's literary works and, in turn, bring attention to his own, realistic, works. Twain never once clearly asserts his work to be of a better quality than that of Cooper's, however, he does articulate the inferior nature of Cooper's novels. Obviously, Twain's ridicule of Cooper serves a purpose other than to simply raise Twain's self esteem. One may say that Twain's criticism of Cooper acts also as an appraisal of his own, realistic, works.
Another way in which Twain attempts to pull the rug out from under Cooper's feet is through his use of categorization. Specifically, Twain labels himself as a humorist, while he labels Cooper as a novelist. This allows Twain to poke fun at Cooper's novels in a humorous way as well as to depict Cooper as a failure at being a novelist. Another thing Twain's categorization of himself and Cooper allows is to advocate Twain's own literary works, and realism as a whole. Thus, one could describe Twain as writing "behind a mask," similar to female author Louisa May Alcott.
In regard to Twain, he is rewarded for his use of a pen name and label as humorist, not novelist, as he labels Cooper. Thus, Twain allows his literary works to gain popularity through his criticism of Cooper's novels. Consequently, Twain has become a popular figure in American Literature. However, Cooper has lost little or no recognition as a writer due to Twain's humorous reception of his works. As Twain benefits, even minutely, from his criticism of Cooper, Cooper, in turn, remains utterly the same; A father of American Literature.