This book presents results from a four-year project addressing the central question: What factors, challenges, and contexts contribute to and constrain literacy achievement among at-risk adolescent learners with culturally diverse backgrounds? Researchers consider the importance of several, interrelated factors that support the development of adolescents' literacies in multilingual contexts: support from educators, community groups, families, and peers; recognition of the multi-faceted complexity of literacy through multiple, complementary methods of research and assessment; approaches to pedagogy that engage learners' zones of proximal development in humanistic and purposeful ways; and promoting students' vocabulary knowledge, strategies for reading, writing, and learning, and orientations to engaging with epistemic purposes of literacy critically, through multiple media, and with self-confidence.