This book investigates how bilingualism affects children's language, cognitive and narrative abilities. The data sample derives from 209 8-12 years old bilingual children, in three different targeted languages (Greek-English, Greek-German, Greek-Albanian) along with 100 monolingual Greek children. The children completed baseline and experimental tasks measuring their vocabulary, grammar, cognitive skills, and narrative production abilities. The outcome of this work reveals that learning to read and write in two languages is beneficial for the development of language and cognitive skills. A strong case can be made to the growing bilingual communities in Germany and beyond to provide literacy training in both languages within mainstream schools, afternoon classes outside of the curriculum or in community schools.