This landmark volume offers a collection of conceptual papers and empirical research studies that investigate the dynamics of language learning motivation from a complex dynamic systems perspective. The contributors include some of the most well-established scholars from three continents, all addressing the question of how we can understand motivation if we perceive it as continuously changing and evolving rather than as a fixed learner trait. The data-based studies also provide useful research models and templates for graduate students and scholars in the fields of applied linguistics and SLA. This collection of conceptual papers and data-based research studies investigate the dynamics of language learning motivation from a complex dynamic systems perspective. The chapters seek to answer the question of how we can understand motivation if we perceive it as a continuously changing and evolving entity rather than a fixed learner trait.