Lev Vygotsky (1896-1934) was a Russian developmental psychologist, discovered by the Western world long after his early death through tuberculosis at the age of 37. An important thinker, he pioneered the notion that the intellectual development of children is a function of human communities, rather than of individuals. It is now thought that Vygostky's contributions have been paramount in furthering our understanding of child development, and that his ideas were not only ahead of his time but also ahead of ours.
Vygotsky's work includes several key concepts which have been influencing in the field of early childhood development. One of his most important concepts is the Zone of Proximal Development which relates to the gap or difference between what the child can learn unaided and what it can learn with the help of an adult. The ZPD is therefore all the child can achieve when given appropriate support. This concept was later developed by Bruner and is now known as scaffolding. Another important Vygostkyan contribution relates to the development of language as related to thought. This concept is explored in his brilliant book "Thought and Language".
Vygotsky was largely forgotten after his death, and his work in early cognitive development does not appear to have influenced cognitive developmentalists such as Jean Piaget. Vygotsky's work became well known in the United States during the 1980s in part due to the opening of the Soviet Union due to glasnost. Vygotsky's work became extremely influential because it offered a way of reconciling the competing notions of maturation by which a child is seem as an unfolding flower best left to develop on their own, and the notions of behaviourism in which a child is seen as a blank slate onto which must be poured knowledge.