Lev Vygotsky was born November 17, 1896
and died June 11, 1934. He was born in in the western region of the Russian Empire. His formal work in psychology did not begin until 1924 when he began collaborating with Alexei Leontiev and Alexander Luria.
According to Vygotsky, the zone of proximal development is "the distance between the actual developmental level as determined by independent problem solving and the level of potential development as determined through problem solving under adult guidance, or in collaboration with more capable peers."