My classmates and I want to browse in the stacks for literary criticism on American authors. Where can we find items like that?
American authors are found in the PS section in the main collection, and that does include literary criticism. Works by an author, and the criticism will be shelved together.
If you want to pinpoint a specific author or authors, your best bet is to use the catalog, to at least find the specific area where that person's works are.
To do this, go to WorldCat (link below) and type in your author's name, and the word criticism. For example, if you are searching Alice Walker type Alice Walker and criticism.
To narrow it down, once you find a good title, click on the title link and look to the right. You will see a Library of Congress subject heading with your author's name and criticism. If you click on that, you will retrieve all of the literary criticism books for that person. Clicking on the title link also retrieves the call number.