Book excerpt: Focusing on adolescent multilingual writing, this text problematizes the traditional boundaries between academic writing in school contexts and self-initiated writing outside of the formal learning environment. By reconceptualizing the nature of adolescent multilingual writing, the author establishes it as an interdisciplinary genre and a key area of inquiry for research and pedagogy. Organized into six chapters, Reconceptualizing the Writing Practices of Multilingual Youth provides an in-depth examination of the writing practices of multilingual youth from sociocultural and social practice perspectives. Drawing on first-hand research conducted with young people, the text questions the traditional dichotomy between academic writing and non-formal equivalents and proposes a symbiotic approach to exploring and cultivating the connections between in- and out-of-school literate lives. By highlighting a bidirectional relationship between formal and informal writing, the text advocates for writing instruction that helps adolescents use writing for entertainment, identity construction, creative expression, personal well-being, and civic engagement, as well as helps them learn to navigate future literacies that we cannot imagine or predict now. This much-needed text will provide researchers and graduate students with a principled overview and synthesis of adolescent multilingual writing research that is significant yet underexplored in applied linguistics, TESOL, and literacy studies.