Encyclopedia entries can be very handy when you are working on choosing a topic. Use them to:
Sometimes a general encyclopedia or Wikipedia may be sufficient. At other times, specialized encyclopedias may be more useful. Encyclopedias written on specific subjects will usually have more detailed information and are written for an academic audience.
Remember that encyclopedias should usually be considered a starting point for research. They won't replace a peer-reviewed, scholarly source.
The duPont-Ball Library subscribes to a few databases that include many specialized encyclopedias, and we also have print and electronic encyclopedias.