To Say Nothing of the Dog
To Say Nothing of the Dog, or, How We Found the Bishop's Bird Stump at Last , by Connie Willis I just love this novel. I've read it several times and it's still great. It's especially good if you're feeling a bit down and in need of distraction, because it's a comedy. I might even call it a screwball SF comedy with lots of fun literary hat tips. Connie Willis is a very well-known SF author, and you should definitely read her stuff (though she does have a tendency to be reaalllly lengthy sometimes). Some of her stories take place at a future Oxford University, where historians travel back in time to observe and experience events. Here, time travel exists, originally invented by criminals hoping to plunder the past, but relegated to academics because nothing can be brought back and the space-time continuum (a self-protective system) won't allow people to get anywhere near important people or events. You can't assassinate Hitler by time-travel.