Where would a person find The Encyclopedia of Associations?

If a patron comes in looking for a particular set of encyclopedias, you can look it up in the catalog. If you can't find it send them down to the LC desk for  Reference and Research Assistance. It may be that the patron does not have the exact title correct. Encyclopedias can be tricky to find so the best thing to do when you are unsure about something is to send them downstairs. Let them know that you don't see it in the catalog but the Reference Librarians may be more familiar and able to find it for them.