WorldCat.org is a free interface to the database OCLC WorldCat which libraries use to share cataloging records and loan materials to one another through InterLibrary Loan. Each library that owns an item tags the record in the database so that other libraries know that they own it. Most academic libraries provide access to a slightly more robust version of the database than this free one, but this is very useful for non-affiliated people. You can search for materials in local libraries, or distant ones, and then use that information to go pick it up yourself or place an InterLibrary Loan request through your local library.
This is what the main screen looks like
A search for a recording of Edward MacDowell retrieved this and you'll see that UW-Milwaukee owns this
