In my review of Bellwether by the same author, I mentioned that that book was really Science fiction, where the plot is based on Science, such as a theory, rather than Engineering fiction, where the plot is based on an engineering breakthrough, such as the development of a Time machine.
Well this is the next Connie Willis book that I've read, and it is about a time machine. Real Engineering fiction, of the sort that is usually called Science Fiction. She does go on to write a third book, To Say Nothing of the Dog in which she bases the plot around the science of the time machines. But in this case it is a traditional time travel story.
That is not to say that it isn't a very good one.
I did not think it was as good as Bellwether, but others disagree. I think it depends on how sentimental you like your stories. The Doomsday book is a very sentimental piece, with a lot of tragedy and pain. If that is your sort of reading then you'll really love it. That is not my type of story, so I merely thought it was very, very good.
What I did like was the attention to detail that went into the work. The picture of the middle ages that came out of this was very realistic, according to my limited knowledge of the times. This is the reason for the above mentioned tradgedy and pain. That is what the middle ages was like. For further gruesome detail see A Vision of Light.
It is possible that Connie intended the horrible details of pastoral life prior to the industrial revolution to have some sort of shock value. This would depend on the level of education of the reader. For someone whose view of the Age of Chivalry is based on King Arthur movies this could indeed be a sudden wake up call, however amoung my circle of friends it did not. Order Doomsday Book