The Johnson County Library has a periodic "meet the staff" series - here's a recent profile of superpatron Marge Vallazza:
Marge Vallazza started working as a Circulation Clerk at the Antioch Library in January 2001. Before coming to work at the Antioch Library she had been a “superpatron” both when Antioch was the main library and after when it was a branch. A superpatron is library slang for someone who tarries at the library and checks out a lot of books—in other words, just the kind of patron the library wants. While a superpatron Marge teased the Antioch staff about coming to work for the library following retirement.