You might be wondering why a English 433 student would consult subject encyclopedias and other tertiary sources.  The quick answer is that it can't hurt to make sure you have a good sense of how your research question fits in with other scholarly research that has been done--and the bibliographies at the end of encyclopedia articles are an efficient way to make sure you know who the scholars are who've been working on this topic.

Remember that tertiary sources are intended to fill in gaps in your knowledge or jumpstart your research; they should not be cited as scholarly secondary sources for your project.