To Say Nothing of the Dog is a novel by Connie Willis. The story is set in Oxford, England, about 60 years into the future, after Time Travel has not only been invented, but pretty much everyone except historians has lost interest in it. This is mainly because it turns out that you can't bring things from the past to the future, or at least, you aren't supposed to be able to. Most of the history of this period and rules of time travel are laid out in Willis' earlier novel Doomsday Book, which takes place in the same universe.