Lev Semyonovich Vygotsky (Russian: Лев Семёнович Выготский, [vɨˈɡotskʲɪj]; Belarusian: Леў Сямёнавіч Выгоцкі; November 17 [O.S. November 5] 1896 – June 11, 1934) was a Russian psychologist, best known for his work on psychological development in children ...
(wikipedia)