Alain Badiou is arguable the most important and original philosopher working in France today. Swimming against the tide of postmodern orthodoxy, Badiou's work revitalizes philosophy's perennial attempt to provide a systematic theory of truth. This volume presents for the first time in English a comprehensive overview of Badiou's ambitious system. Beginning with Badiou's controversial assertion that ontology is mathematics, this volume sets out his theory of the emergence of truths from the singular relationship between a subject and an event. Also included is a substantial extract from Badiou's forthcoming work on the logics of appearance and the concept of world, presented here in advance of its French publication. Ranging from startling re-readings of canonical figures (Spinoza, Kant and Hegel) to decisive engagements with poetry, psychoanalysis and radical politics, Theoretical Writings is an indispensable introduction to one of the great thinkers of our time.