Maintains that, although Leontiev's sociocultural orientation and its activity emphasis were inherited from Vygotsky's theory, the two men's theoretical motives and goals differed. Vygotsky's focus on symbolic mediation transforming psychological processes and Leontiev's on activities leading to internalization of action in mental processes were complementary. However, Leontiev's theory remained poorly articulated and was limited by reliance on Marxist influences. (Author/KB)