Alain Badiou is arguably the most original and influential philosopher working in France today. Working against the tide of postmodern orthodoxy, Badiou revitalizes philosophy's perennial attempt to provide a systematic theory of truth. Theoretical Writings presents, in Badiou's own words, 'the theoretical core of [his] Philosophy'. Beginning with the controversial assertion that ontology is mathematics, the chapters step the reader through his key concepts of being, subject and truth via startling re-readings of canonical figures including Spinoza, Kant and Hegel and engagements with poetry, psychoanalysis and radical politics. Theoretical Writings is an indispensable introduction to one of the great thinkers of our time.