I nominate Doomsday Book by Connie Willis.
From Amazon:
Winner of both the Hugo Award for Best Novel and the Nebula Award for Best Novel.
For Kivrin, preparing an on-site study of one of the deadliest eras in humanity's history was as simple as receiving inoculations against the diseases of the fourteenth century and inventing an alibi for a woman traveling alone. For her instructors in the twenty-first century, it meant painstaking calculations and careful monitoring of the rendezvous location where Kivrin would be received.
But a crisis strangely linking past and future strands Kivrin in a bygone age as her fellows try desperately to rescue her. In a time of superstition and fear, Kivrin -- barely of age herself -- finds she has become an unlikely angel of hope during one of history's darkest hours.
Five years in the writing by one of science fiction's most honored authors, Doomsday Book is a storytelling triumph. Connie Willis draws upon her understanding of the universalities of human nature to explore the ageless issues of evil, suffering and the indomitable will of the human spirit.
From Publishers Weekly:
This new book by Hugo- and Nebula-award-winning author Willis ( Lincoln's Dreams ) is an intelligent and satisfying blend of classic science fiction and historical reconstruction. Kivrin, a history student at Oxford in 2048, travels back in time to a 14th-century English village, despite a host of misgivings on the part of her unofficial tutor. When the technician responsible for the procedure falls prey to a 21st-century epidemic, he accidentally sends Kivrin back not to 1320 but to 1348--right into the path of the Black Death. Unaware at first of the error, Kivrin becomes deeply involved in the life of the family that takes her in. But before long she learns the truth and comes face to face with the horrible, unending suffering of the plague that would wipe out half the population of Europe. Meanwhile, back in the future, modern science shows itself infinitely superior in its response to epidemics, but human nature evidences no similar evolution, and scapegoating is still alive and well in a campaign against "infected foreigners."p. 204 This book finds villains and heroes in all ages, and love, too, which Kivrin hears in the revealing and quietly touching deathbed confession of a village priest.
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