Research results over the past decades have consistently demonstrated that a key reason why many second language learners fail - while some learners do better with less effort - lies in various learner attributes such as personality traits, motivation, or language aptitude. In psychology, these attributes have traditionally been called "individual differences." The scope of individual learner differences is broad - ranging from creativity to learner styles and anxiety - yet there is no current, comprehensive, and unified volume that provides an overview of the considerable amount of research conducted on various language learner differences, until now. Each chapter in this new volume focuses on a different individual difference variable. Besides a review of the relevant second language literature, Zoltan Dornyei presents a concise overview of the psychological research involving each topic. A key concern for the author has been to define the various learner factors as measurable constructs and therefore the discussion includes a summary of the most famous tests and questionnaires in each domain. A wide range of readers will benefit from this book - students in linguistics, applied linguistics, modern languages, and psychology programs; second language teachers participating in in-service training courses; and researchers in second language acquisition and psychology.