If you are trying to find companions to philosophy, there are two major series:
You could do a title search in the library catalog to browse ALL the philosophy companions that we own. However, I would suggest doing a search for the companion series and the name of the philosopher you desire. Example:
If you don't find what you want when searching the EWU Libraries catalog, then you can try searching the Summit catalog and order it from another university library. The philosophy department also has a good amount of resources in their library, so you can also check with your department.
Here is another useful work: the Oxford Companion to Philosophy. 2005. Edited by Ted Honderich. JFK Library: Reference (Non-Circulating) B51 .O94 2005. An online version is also available.