Often times using a reference book to begin your research can be the most helpful starting point to explore a topic or find some contextual information. However, even if you have some knowledge of your topic, a reference book could be used to discover leads to more in-depth resources.
You can find general, subject-specific, or data-focused reference books like some of these below searching InfoKat Discovery.
Here is a short sample list of reference e-books to get you started.
Additional resources for learning more about a topic are reference databases which are searchable collections of full-text encyclopedias, almanacs, dictionaries, and other specialized reference sources. Some reference databases include: