When you need to find literary criticism about a specific author or a specific work, try using the special field limiters in MLA International Bibliography that let you do just that!
Primary Subject Author
After entering the author you are researching, use the Select a Field option and choose Primary Subject Author from the pull down menu.
Primary Subject Work
And you can do something similar with many of the most studied literature. After entering the work you are researching, use the Select a Field option and choose Primary Subject Work from the pull down menu.