The Girl in the Mask by Marie-Louisen Jensen (Published by Oxford University Press, March 1, 2012)
Set in Georgian England, fifteen-year-old Sophia is trapped by the limitations of living in a man's world. Forced by her father to give up everything she loves, Sophia is ordered to make a new life in Bath. By day, she is trapped in the social whirl of balls and masquerades. By night, she secretly swaps her ball gowns for breeches, and turns to highway robbery to get her revenge . . . When one man begins to take a keen interest in her, Sophia must keep her distance, or risk unmasking her secret life.
I loved all of Marie-Louise Jensen's previous books - she writes wonderful romantic YA historical fiction. So I can't wait to read her next book!