Seminal works are highly original and influential works that have led to the further development or understanding of a subject. There is no one tool for discovering the most important works on a topic, but there are some ways to build your knowledge of the scholarly conversation surrounding a topic.
Use the library databases and Discover to search for articles and books on your topic. As you find articles and books on your topic, pay attention to their works cited lists and bibliographies. What articles and books are they citing? Notice in particular any works that are cited across the articles and books you've found. Repetition can be a sign that they're important.
Some databases include information about how many times an article or book has been cited by other sources. This is not a foolproof way of determining the relative importance of an article or book, however. No two databases include all of the same works, and it's possible an article or book has been cited many times because many people disagree with it. It's worth checking a few of the sources citing a work to see if that's the case or not.
Aside from offering background information on authors, literary themes, movements, and genres, reference works sometimes included brief bibliographies or lists of further reading at the end which point out seminal or important works on a topic. A couple of examples:
The Oxford encyclopedia of American literature by 
Oxford Encyclopedia of British Literature by A companion is a handbook or guide. You'll often find these for major authors, literary periods and genres. Companions usually contain collections of essays or entries on different aspects of the topic covered, often including bibliographies of additional sources to consult. Sometimes these are flagged as seminal or important. A critical or scholarly edition of a literary work often includes not just the primary text itself, but also a selection of critical essays on the author and work. To search for companions and critical editions, use these library catalogs:
Aside from seminal works, it's also important to include at least some newer scholarship in your research. The way we study literature changes over time: new schools of critical thought arise, levels of scholarly rigor vary, new techniques are found for studying literature, and new points of view are added to the conversation. We also continue to learn new things even about works that are hundreds of years old.
Most databases will allow you to limit your search to a specific date range. For example, the MLA International Bibliography's 's Search Options include a Publication Date menu for this purpose. You can also use the Publication Date slider on the results page to target a specific date range after you've run your search.
Review articles summarize the current (as of the time of the article's writing) research on a topic. The author (or authors) offer their analysis of the research, too. Review articles can help you identify the scholars working on your topic, recent advances or discoveries, current debates, gaps in research, and also give you an idea of where the research might be headed next.
Found a good article or book on your topic? A useful way to find more information that's relevant to your research is to check its works cited or references list. Another strategy for discovering additional relevant information - and seeing where the scholarly conversation on your topic has gone since the article or book you first found was published - is to find out if any other scholars have cited it. What follows are some tips on tracking down citations in either direction.
Browse through an article's, book's (or book chapter's) references or works cited list. If you see any references that look like they are also about your research topic, search for them in Discover.
Search for your article or book in Google Scholar. For some results, Google Scholar will show a Cited By link that, when clicked on, will take you to a list of other articles and/or books that cite the one you just searched.
