Dual immersion, a popular new way to foster bilingualism, is capturing the attention of parents and educators alike. By bringing together children from diverse backgrounds to learn each other’s languages in a natural setting, it has proved far more effective at cultivating fluency than traditional approaches. But how do these programs actually work? What goes on in dual immersion classrooms? And what is it that makes them so effective? Diary of a Bilingual School answers these questions with a unique mix of narratives and analysis. Depicting a year in the life of a second-grade classroom, it demonstrates what can happen when the instruction is bilingual and the curriculum is constructivist.