To Say Nothing of the Dog by Connie Willis.
Like Doomsday Book, Blackout, All Clear, and Firewatch it features Oxford's time travelling historians, though the major characters in the other books are minor characters in this one.
From Booklist--
What a stitch! Willis' delectable romp through time from 2057 back to Victorian England, with a few side excursions into World War II and medieval Britain, will have readers happily glued to the pages. Rich dowager Lady Schrapnell has invaded Oxford University's time travel research project in 2057, promising to endow it if they help her rebuild Coventry Cathedral, destroyed by a Nazi air raid in 1940. In effect, she dragoons almost everyone in the program to make trips back in time to locate items--in particular, the bishop's bird stump[though they are unclear about what it is exactly]....
Time traveler Ned Henry is suffering from advanced time lag and has been sent, he thinks, for rest and relaxation to 1888, where he connects with fellow time traveler Verity Kindle and discovers that he is actually there to correct an incongruity created when Verity inadvertently brought something forward from the past.
Take an excursion through time, add chaos theory, romance, plenty of humor, a dollop of mystery, and a spoof of the Victorian novel, and you end up with what seems like a comedy of errors but is actually a grand scheme "involving the entire course of history and all of time and space that, for some unfathomable reason, chose to work out its designs with cats and croquet mallets and penwipers, to say nothing of the dog...."
--Sally Estes
It won both the Hugo and Locus Awards in 1999, and was nominated for the Nebula Award in 1998.
http://inkmesh.com/ebooks/to-say-not...+Connie+Willis