Motivation is one of the key learner characteristics that determine the rate and success of language learning: It provides the primary impetus to embark upon learning and later the driving force to sustain the long and often tedious learning process. Due to the complex nature of language itself - it is at the same time a communication code, an integral part of the individual's identity, and the most important channel of social organization - language learning motivation is a multifaceted construct, consisting of a range of different motives associated with certain features of the language, the language learner, and the learning situation. This volume addresses this intriguing complexity by first providing a comprehensive overview of the recent development and the most important research directions in the field, and then by offering a selection of data-based studies by some of the best-known motivation researchers. These research papers conceptualize the motivation complex in different yet complementary ways, proposing and empirically validating various constituent attitudes, orientations and motives - hence the title of the volume.