"As a young teacher on Martha's Vineyard, Mary Lambert feels restless and adrift. So when a league of missionaries invite her to travel abroad, she knows it's a once in a lifetime opportunity. Paris is home to a pioneering deaf school where she could meet its visionary instructors Jean Massieu and Laurent Clerc--and even bring back their methods to help advance formal deaf education in America! But the endeavor comes at a cost: The missionaries'...