What topics did Michel Foucault examine in Madness and Civilization?

In his early work Madness and Civilization: A History of Insanity in the Age of Reason (1961), Michel Foucault examined how Western philosophy and science defined and applied the concept of reason by contrasting it with its "other"—those classified as "devoid of reason," or the insane.1

Foucault explored how this definition of reason facilitated the mistreatment and oppression of the insane, who were confined in prisonlike asylums and, in the 20th century, subjected to tortuous psychological treatments. The work serves as a critique of how society uses the label of insanity to exert control, concluding with an homage to "unreason" as a force that resists the "gigantic moral imprisonment" often disguised as the liberation of the insane.1