BOOK REVIEW: Input, Interaction, and the Second Language Learner. Susan M. Gass. Routledge, New York (2018).189 pp., ISBN: 978-1-138-04322-0

The 2018 edition of 'Input, Interaction, and the Second Language Learner', along with a new preface, explores the roles of input and interaction in second language development and introduces the research studies that have shaped SLA from twenty years ago until now. It refers to diverse theories and surveys the stages that input go through before it can be used productively by language learners. Gass proposes input-interaction model that embraces diverse models in the literature and asserts that all models complement, rather than contradict, each other.