To write a good comparative essay that compares two different authors’ works is very difficult.
If two books have similarities, is it really such a good idea to write a comparative essay about them? There are many books to choose from. What benefit is there in comparing those particular books?
The final essay may read like this, “These authors, which I have read, are doing some similar things.” Maybe that is a little useful? A reader that has read one of the books might think, “Well, I suppose if I read this other author, it will have a similar feeling to this book I already read.”
It seems that it makes a bit more sense to compare the work of an author with his other works. In the case that two authors influence each other, that might also make an interesting essay.
There is an essay that compares works by two different authors in a well-defined literary or philosophical movement. A critic might be able to identify the people or works that go together, but a student? In these cases, which deal with well-defined movements, history or influence is important, a basic feature for such essays. Who said it best or first? How did another writer respond to that?
In a comparative essay, there is often an artificial triangle, between the works and some theory. Theory is a tool that connects the works, to show in each story a shared concept.
In another fashion, one author’s writing is used to analyze the other and vis-a-versa. Subtextually, writers make points to justify what is happening in a story. Between two similar stories, these points can be used to illustrate what is happening in the other story. Of course not exactly, but this is how the paper works: there is a “Big Theme” that is shared by both stories and two “little themes” one for each story. Their explanations will never be the same, and so the differences will mount until the “little themes” oppose each other.
A poorly written comparative essay convulutes the meaning of both works. More often than not, comparing and contrasting two stories is a mental exercise, and may not generate anything meaningful.