For more than a quarter of a century, the polemics surrounding educational reform have centered on two points of view: those who favor a 'progressive' child-centered form of education, and those who would prefer a return to a more structured, teacher-directed curriculum, which emphasizes basic knowledge and skills. Vygotsky's social constructivist theory offers an alternative solution, placing stress on co-construction of knowledge by more and less mature participants engaging in joint activity together, with semiotic mediation as the primary means whereby the less mature participants can seek solutions to everyday problems, using the resources existing in society. In addition to using illustrative examples from classroom studies, a comparative analysis of the theories and complementary developments in works by Vygotsky, and the linguist M. A. K. Halliday, are provided. This unique volume will be of tremendous benefit to those in the field of education, as well as to sociolinguists, psychologists and researchers.