Miguel de Beistegui identifies the impetus and driving force behind Deleuze's philosophy and its concepts. By returning Deleuze's thought to its source--or, following Deleuze's own vocabulary, to what he calls the event of that thought--Beistegui extracts its inner consistency: immanence. Chapters dealing with the status of thought itself, ontology, logic, ethics, and aesthetics reveal the manner in which immanence is realized in every one of these classical domains. Beistegui ultimately argues that immanence is an infinite task and that transcendence is the opposition with which philosophy will always need to reckon.