In the present Collected Works, the main works of the eminent Soviet psychologist Lev Semyonovich Vygotsky are presented for the first time with sufficient completeness. Vygotsky was a prolific writer: in less than 10 years of activity as a professional psychologist he wrote about 180 works. Of these, 135 have been published, and 45 await publication. [2] Many of Vygotsky's publications have become bibliographic rarities.