It was the worst Parisian flood in 250 years. Two blocks from Notre Dame, the river stood eight feet high in the streets. The Metro was flooded. This was a complex historical background to research. Love your librarian .
Great details come from obscure books.
Research librarians can cut days off finding the right books. Librarians know the arcane mantras under which information is filed. They know what books aren't entered in the electronic catalog. Time after time, research librarians have found me great sources I would never have discovered. Best of all, they can sometimes get you into the stacks, the closed areas of libraries.