Deleuze is a key figure in poststructuralist French philosophy. Considering himself an empiricist and a vitalist, his body of work, which rests upon concepts such as multiplicity, constructivism, difference and desire, stands at a substantial remove from the main traditions of 20th century Continental thought. His thought locates him as an influential figure in present-day considerations of society, creativity and subjectivity. Notably, within his metaphysics he favored a Spinozian concept of a plane of immanence with everything a mode of one substance, and thus on the same level of existence. He argued, then, that there is no good and evil, but rather only relationships which are beneficial or harmful to the particular individuals. This ethics influences his approach to society and politics, especially as he was so politically active in struggles for rights and freedoms. Later in his career he wrote some of the more infamous texts of the period, in particular, Anti-Oedipus and A Thousand Plateaus. These texts are collaborative works with the radical psychoanalyst Félix Guattari, and they exhibit Deleuze’s social and political commitment. Gilles Deleuze began his career with a number of idiosyncratic yet rigorous historical studies of figures outside of the Continental tradition in vogue at the time. His first book, Empirisism and Subjectivity, is a study of Hume, interpreted by Deleuze to be a radical subjectivist. Deleuze became known for writing about other philosophers with new insights and different readings, interested as he was in liberating philosophical history from the hegemony of one perspective. He wrote on Spinoza, Nietzche, Kant, Leibniz and others, including literary authors and works, cinema, and art. Deleuze claimed that he did not write “about” art, literature, or cinema, but, rather, undertook philosophical “encounters” that led him to new concepts. As a constructivist, he was adamant that philosophers are creators, and that each reading of philosophy, or each philosophical encounter, ought to inspire new concepts. Additionally, according to Deleuze and his concepts of difference, there is no identity, and in repetition, nothing is ever the same. Rather, there is only difference: copies are something new, everything is constantly changing, and reality is a becoming, not a being. He often collaborated with philosophers and artists as Félix Guattari, Michel Foucault, Guy Hocquenghem, René Schérer, Carmelo Bene, François Châtelet, Olivier Revault d'Allonnes, Jean-François Lyotard, Georges Lapassade, Kateb Yacine and many others.