To Say Nothing of the Dog - Connie Willis - Bog

"Ned Henry is badly in need of a rest. He's been shuttling between the twenty-first century and the 1940s in search of a hideous Victorian vase called "the bishop's bird stump" as part of a project to restore the famed Coventry Cathedral, destroyed in a Nazi air raid. But then Verity Kindle, a fellow time traveler, inadvertently brings back something from the past. Now Ned must jump to the Victorian era to help Verity put things right--not only to save the project but also to prevent altering history itself"--