Lev Vygotsky (1896-1934) was a Soviet psychologist who focused his profound intellect on the fields of  developmental psychology and pedagogy. Though he died at the age of 38 and his writings were only published posthumously and not known in the West until after 1958, his work has, since that time, been demonstrated to have had tremendous influence on other writers and thinkers (see Genealogy of Cultural-Historical Activity Theory, below). Educational theorists and philosophers have increasingly been drawn to Vygotsky's work, seeing in it, "a superior understanding of the relationship between the educator and the educated, in which the educator must 'negotiate' with the child or student who is credited with an active role in the learning process."¹ Vygotsky's conception of a Zone of Proximal Development (ZPD), as "...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,"² has obvious implications for multiple facets of Process Education, including facilitation, modeling, and collaborative/cooperative learning.

Vygotsky's influence, though more recent than that of many others, is profound. Consider the following quotes from Mind in Society: Development of Higher Psychological Processes:
Learning is more than the acquisition of the ability to think; it is the acquisition of many specialised abilities for thinking about a variety of things. (Learning Skills)
Development, as often happens, proceeds here not in a circle but in a spiral, passing through the same point at each new revolution while advancing to a higher level. (Levels of Learner Knowledge & Bloom's Taxonomy)
As in the focus of a magnifying glass, play contains all developmental tendencies in a condensed form and is itself a major source of development. (Learning Activities)