Sylvia Plath’s unpublished poems and short stories from her high school years (1947–50) have received little sustained scholarly attention. Yet they offer surprising clues of the writer Plath would become, and reveal the strong influence that modernist poetry and progressive politics had on her aesthetic development. They also suggest the crucial role Plath’s high school English teacher played in guiding her aesthetic and political instincts. The archive shows how Plath’s adolescent literary apprenticeship laid the foundation for two of the most important works of the twentieth century, The Bell Jar and Ariel.