The Grand Sophy by Georgette Heyer
So much fun. The details of language and expressions, customs and clothing of Regency England are incredible.
I didn't appreciate Georgette Heyer when I was younger, mostly because this historical period, which she writes about the most, is not my favorite time period: I prefer Tudor, Stuart or Medieval Times. And Heyer DID write in the medieval period, for instance "My Lord John" which I should re-read, but I feel that her greatest strength is the Regency. And "The Grand Sophy" is one of the best.
I wanted to give it 5 stars but there are a couple of things that are off--as noted by other reviewers and leave a bad after taste, such as the character of the money lender and also the fact that the romantic interests are first cousins.