This article traces historical uses of the phrase "why girls go wrong" to provide a context for analysis of Progressive Era reading guidance for girls and then turns to actual girls' responses to reading. The historic context depicts the milieu in which young women and the advisors who sought to guide them lived and read as a time of intense concern with adolescent female sexual activity. Further, the era also witnessed suspicion about the way that public spaces were used, particularly by women and girls. Librarians constructed, through arguments that selected titles that represented persuasively pure and feminine ideals, a female sphere in the public library. Images of the early twentieth-century library as a wholesome, protective space for young women acknowledged contemporary social issues and responded to ensure that the bookish domains would be seen as appropriate venues for adolescent girls.