You might be wondering why a English 381 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.
Cambridge Companions are a series of authoritative essay collections that synthesize the most important aspects of a topic. Each volume is edited by a leading scholar in the field and offers essays written by experts. Look for Companions on specific authors, genres, themes or movements, and time periods. The companions below are especially relevant for the works of John Milton.
Literature Compass publishes peer-reviewed, state-of-the-field articles from across the discipline. Review articles summarize the current scholarship on a topic and offer an analysis. They can help you identify the scholars working on your topic, recent developments, current debates, gaps in research, and also give you an idea of where the research might be headed next.
More survey articles: