Connie Willis is one of the few authors capable of humor, humanity, and what must be an ungodly amount of research, and she brings all these skills together in the masterful Doomsday Book.
In near-future Oxford, where time travel for purposes of historical research is relatively common, an eager young historian travels to medieval times. Unfortunately, things immediately go very wrong for her. Then a devastating pandemic hits the present day, and no one is able to help her, or even know she’s in trouble.
Recommendation: Read it. The characters range from deeply human to hilariously Dickensian, and the descriptions of the horrors of daily life in medieval times are some of the best I’ve ever read. Oh, and it’s a great story that won both the Hugo and Nebula awards.