Mark Kelly details and criticises all of Foucault’s major political ideas: the historical relativity of knowledge; exclusion and abnormality; his radical reconception of power; his historical analysis of biopolitics in terms of discipline and biopower; his concept of governmentality; and his late work around ethics and subjectivity. Kelly shows how Foucault’s positions changed over time, how his thought has been used in the political sphere and examines the importance of his work for politics today.