Introduction. Learning, using and unlearning more than one language Annick De Houwer and Lourdes Ortega; Part I. Bilingual Learning and Use at Five Stages of Life: 1. Becoming bilingual in early childhood Ludovica Serratrice; 2. Bilingualism from childhood through adolescence Martha Bigelow and Penelope Collins; 3. Young bilingual adults Kellie Goncalves; 4. Bilingualism in midlife David Singleton and Simone E. Pfenninger; 5. Language and older bilinguals Mira Goral; Part II. The Larger Contexts of Bilingualism: 6. Ideologies of language, bilingualism, and monolingualism Janet M. Fuller; 7. Bilingualism and the law Philipp S. Angermeyer; 8. Language planning and policies for bilingualism Joseph Lo Bianco; 9. The economics of bilingualism Francois Grin; Part III. Contexts for Bilingual Learning and Unlearning: 10. The nature of exposure and input in early bilingualism Sharon Armon-Lotem and Natalia Meir; 11. Becoming bilingual through additive immersive programs Maria Juan-Garau and Roy Lyster; 12. Foreign language learning from early childhood to young adulthood Carmen Munoz and Nina Spada; 13. Supporting bilingualism in adult first generation migrants James Simpson; 14. Unlearning and relearning of languages from childhood to later adulthood Merel Keijzer and Kees De Bot; Part IV. The Dynamics of Bilingualism across the Lifespan: 15. The measurement of bilingual abilities Jeanine Treffers-Daller; 16. Highly proficient and gifted bilinguals Adriana Biedron and David Birdsong; 17. Language choice in bilingual interaction Annick De Houwer; 18. First language attrition: from bilingual to monolingual proficiency? Barbara Kopke; Part V. Bilingualism Research across Disciplines: 19. Bilingualism in clinical linguistics Carol Scheffner Hammer and Lisa A. Edmonds; 20. Doing and undoing bilingualism in education Ofelia Garcia and Ruanni Tupas; 21. Second language acquisition as a road to bilingualism Lourdes Ortega; 22. Bilingualism in cognitive science: the characteristics and consequences of bilingual language control Kenneth R. Paap; 23. Bilingualism in neurolinguistics: from static to dynamic approaches Arturo E. Hernandez; Part VI. Bilingual Connections: 24. Bilingualism and sign language research Gladys Tang and Felix Sze; 25. Bilingualism and bidialectalism Jean-Pierre Chevrot and Anna Ghimenton; 26. Bilingualism and language contact Suzanne Aalberse and Pieter Muysken; 27. Bilingualism and multilingualism Suzanne Quay and Simona Montanari.