Reference materials are excellent resources for providing an overview of the subject you are researching. They will provide well-known facts on literary authors and their works; historical and political events that may have impacted their work; the society and culture in which they lived and worked and/or may have based their work upon; as well as the impact of their work on future generations. They are trustworthy and reliable, giving you the correct information you will need for your research papers and presentations.
Reference books, either in print or electronic format, will also provide you with keywords and terms to use in your searches through the library catalog or databases. If you are searching for a research topic, using the overview on a subject that a reference source provides can spark the idea for a researchable thesis question.