It is less known that Luria's main interests, before the war, were in the field of psycho-semantics (that is, research into how people attribute meaning to words and instructions). He became famous for his studies of low-educated populations in the south of the Soviet Union showing that they use different categorization than the educated world (determined by functionality of their tools). He was one of the founders of Cultural-Historical Psychology, and a leader of the Vygotsky Circle, also known as "Vygotsky-Luria Circle". Apart from his work with Vygotsky, Luria is widely known for two extraordinary psychological case studies: "The Mind of a Mnemonist", about Solomon Shereshevsky, who had highly advanced memory; and "The Man with a Shattered World", about Lev Zasetsky, a man with a severe traumatic brain injury.