Doomsday Book starts off slow, but the second half is as intense--and moving--as anything I've read in a long time. It's a time travel story in which a young Oxford student, Kivrin, is sent back to the middle ages for two weeks, to the year 1320. Her mentor, Professor Dunsworthy, fears that something's gone amiss and tries to get her back safely , but in the meantime an influenza epidemic hits the Oxford area and he's unable to do anything. I really can't say enough good things about this story. Kivrin, the heroine, starts off as almost flippantly over confident, then becomes panicked, then develops into a strong, capable person, and by the story's end has become completely transformed. There are a number of other great characters, both in the modern-day story and in the medieval story.
I gave this four stars for the slow start and because the Big Reveal, from the modern day side, is constantly delayed, even though we know it's coming. I know why the author had to do this, but she could have made the delays a bit less transparent.
I'll definitely read Doomsday Book again, and that's not something I frequently do. If you're a fan of time-travel stories, or if you're interested in the Middle Ages, or if you just like a good story, you'll like this book. The author ratchets up the intensity (maybe the slow start was deliberate) until you can't stop reading.
Update: I've read this book again and liked it even more than I did the first time. Really makes you feel the hopelessness of the Black Death.