To Say Nothing of the Dog by Connie Willis

To Say Nothing of the Dog defies easy categorization.  It is a hard science fiction novel: the plot revolves around time travel, with its paradoxes and social effects as central to the actions of the characters.   It is a romantic mystery novel:  the lead characters have several mysteries to solve, which they do while falling in love referencing the great 1930′s mystery detective teams.  It is a madcap comedy and it is a historical novel, set in 1880′s and 1940′s England.  Above all, it is a delightful read and a book that stands up to multiple rereads.