"A Noble Masquerade" by Kristi Ann Hunter

Lady Miranda Hawthorne is not looking forward to her fourth season in London. She's never been able to live up to her mother's definition of a lady, and she refuses to marry any man who is only looking at her for the connections she brings as a duke's sister. Meanwhile, in order to process the pressures she's facing, she writes letters she never intends to send to the duke of Marshington, her brother's friend from school who Miranda has never met but whose exploits are legendary. Surely if anyone can understand her, it would be Marshington.

Ryland, duke of Marshington, has been busy serving his country as a spy. His latest role has him disguising himself as a valet to his former schoolmate in order to investigate rumors that someone is sending information to France. One night Ryland happens upon one of Lady Miranda's letters to the duke of Marshington—to him!—and he becomes intrigued by this most unusual woman. 

Circumstances force Ryland and Miranda into close companionship, but Miranda still doesn't know who he is. How will she take it when she learns his identity? As danger swirls, can Ryland manage to keep her safe?

Although I really enjoyed the premise at the beginning of the book, I never fell in love with any of these characters the way I hoped to. Ryland drove me crazy with the games he played once Miranda knew who he was. Miranda didn't come off as sympathetic or consistent in character. I also saw the bad guy coming from a long way off. I know this series is a favorite of many so I'm all set to dive into Book 2. Hopefully I'll end up liking it even more than this one.