Sociocultural Theory and Second Language Learning (Oxford Applied Linguistics)

Lantolf is probably the foremost authority on Sociocultural theory and its Vygotskyan psychological approaches to Second Language Acquistion. I used this volume for a comparison of Chomskyan UG and Vygotskyan Sociocultural theory for a Masters level final essay and received 93% for my efforts, much of the cited material came from this volume. Highly recommended!
Together with Dorothy Robbins' comprehensive review of Vygotsky in "Vygotsky's and A.A. Leontiev's Semiotics and Psycholinguistics : Applications for Education, Second Language Acquisition, and Theories of Language (Contributions in Psychology) (Hardcover)", these two books provide more than sufficient research in this interesting and innovative approach to SLA.

The main force behind Lantolf's book is to broaden the base of theories for second language acquisition (SLA). A major theme running through the text is the inadequacy of popular interactionist theories of SLA for explaining and describing language development, and the need for a research framework that accounts for the role of social context and collaborative dialogue. The text starts with a good overview of sociocultural theory, outlining the major aspects of the theory, including activity theory, inner/private speech and the zone of proximal development. The relevance of these areas are then discussed by a number of SLA theorists/researchers, with the aim of calling for a deeper, contextual and qualitative analysis of language learning interactions/tasks, and asserting the efficacy of sociocultural theory in facilitating and explaining effective language learning. A very readable book.