is best known as a philosopher of culture and student of Ernst Cassirer. In this paper, however, I argue that this standard picture ignores her contributions to the development of analytic philosophy in the 1920s and 1930s. I reconstruct the reception of Langer's first book The Practice of Philosophy¾arguably the first sustained defense of analytic philosophy by an American philosopher¾and describe how prominent European philosophers of science such as Moritz Schlick, Rudolf Carnap, and Herbert Feigl viewed her as one of the most important allies in the United States. In the second half of this paper, I turn to Langer's best-selling Philosophy in a New Key (1942) and reconstruct her attempts to broaden the scope of the, by then, rapidly growing U.S. analytic movement. I argue that her book anticipated various developments in analytic philosophy but was largely ignored by her former colleagues. I end the chapter by offering some clues as to why New Key did not incite the same laudatory responses from analytic philosophers as her earlier work.