In Elsinore Noir by Warren Bull, a library patron unfolds a unique theory about Shakespeare's Hamlet. The reader drops by frequently to update the librarian about his developing concept. Hamlet is treated as a noir whodunit in this very entertaining tale.
The Wrong Coffee Shop by Sharon Marchisello is a story of mistaken identity and two coffee shops with the same name. This had a slice-of-life feel, and left me wanting to know what was on that piece of paper! The story had beautifully worded scene descriptions. Nicely done.
When a librarian goes missing from an exclusive and mysterious private library, his replacement becomes too curious for his own good. Ask a Librarian by Jacqueline Seewald is a fast-paced mystery with a light touch of romance and a heavy dose of what's-going-to-happen-next.
Nudger is a PI in DDS 10752 Libra, by John Lutz and Josh Pachter. I kept wondering when a library or librarian would be involved, and was rewarded with a clever twist.