Like many French philosophers, Foucault's academic training ground was the Ecole Normale Superieure, which he entered at age 20 in 1946. Foucault became impressed with Marxism and existentialism during this period, having been exposed to the philosophy of both Hegel and Marx, but was later to change his position on both of these philosophical approaches.
Foucault, in keeping with French tradition, studied the history and philosophy of science and Georges Canguilhem's work greatly inspired him. Through Canguilhem, Foucault became aware of and interested in the inconsistencies in scientific history. His work was also inspired by the structural linguistics approach of Ferdinand de Saussure as well by the psychological studies of Jacques Lacan, and the proto-structuralist examination of comparative religion as presented by Georges Dumezil.
A brilliant scholar, Foucault worked at various French universities before being elected, at age 43, to the position of Professor of the History of Systems of Thought at the highly regarded College de France. Foucault was politically active and became a strong voice for marginalized groups such as the "mentally ill," which was a term he despised, homosexuals and prison inmates. He co-founded the Groupe d'information sur les prisons and continued to lecture at universities worldwide. A year before his death in Paris from AIDS in 1984, Foucault had decided to accept an annual teaching position at the University of California at Berkeley.
Although postmodernist Foucault adamantly separated himself from the existentialist philosophy of Jean-Paul Sartre, both of these French men despised the power of the bourgeois and stood up for the political causes of the marginalized bourgeoisie groups.
Madness and Civilization, The History of Sexuality and Discipline and Punish: The Birth of the Prison are considered by many to be among Foucault's most influential books. He combined philosophy with historical retrospective.
Knowledge, power, and the connection between them form the crux of all of Foucault's work. Foucault believed that mind control is more powerful than physical punishment in establishing social control. Foucault stressed that social control by authorities often masquerades as the sound reasoning of scientific knowledge.
Foucault's work cautions that what we may take to be knowledge, may instead be nothing more than powerful concepts perpetuated by authorities and those concepts may change our understanding of our selves and our world.